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Short answer: to use a Microsoft 365 product key, go to microsoft365.com/setup, sign in with your Microsoft account, enter the 25-character key and choose your country and language. Then open the Services & subscriptions page of your Microsoft account and select Install to get Word, Excel, PowerPoint and Outlook on your PC or Mac.
This guide walks you through redeeming a Microsoft 365 product key, installing the apps, adding more time to your subscription, and fixing the most common problems. The steps come from Microsoft’s support pages, checked in October 2026.
- Where to redeem: microsoft365.com/setup
- Key: 25 characters, works only once
- Account: always the same Microsoft account
- More keys: each key adds time, up to 5 years in total
- Install from: Services & subscriptions in your Microsoft account
Table of Contents
What you need before you redeem
- A Microsoft account. If you already have Microsoft 365 or use Outlook.com, Xbox or OneDrive, use that same account, so all your time and files stay in one place. If you do not have one, you can create it during setup.
- Your 25-character Microsoft 365 product key. For a key bought online it is in the email from the shop.
- A PC or Mac with an internet connection to download and install the apps.
Redeem the key on the account of the person who will use Microsoft 365 Personal. The subscription is for one person, so it should not be redeemed on a shared family account. Keep the email with your key private until you have redeemed it: whoever redeems a key first gets the subscription.
How to redeem a Microsoft 365 product key
Follow these steps from Microsoft:
- Go to microsoft365.com/setup in your web browser.
- Sign in with your Microsoft account, or create a new one.
- Enter your 25-character product key if you are asked for it.
- Select your country or region and your language.
- Follow the last prompts to finish redeeming the key.
For a Microsoft 365 subscription, Microsoft may ask you to add a payment method for automatic renewal. You can turn off recurring billing later on the Services & subscriptions page of your Microsoft account. Microsoft also explains where to enter your product key for each type of product.
How to install Microsoft 365 apps on your PC or Mac
After the key is redeemed, you install the apps from your Microsoft account. You do not need the key again:
- Go to account.microsoft.com and sign in with the same Microsoft account.
- Open Services & subscriptions.
- Find Microsoft 365 Personal and select Install.
- Choose your language and version if you want to change them, then install.
- Open Word or Excel and sign in with the same account to activate the apps.
You can install the apps on your PC, Mac, phone and tablet. Microsoft 365 Personal lets you be signed in on up to five devices at the same time.
What is included in Microsoft 365 Personal?
Microsoft 365 Personal is the one-person plan. According to Microsoft’s product page, it includes:
- 1 TB of OneDrive cloud storage;
- sign-in on up to five devices at once, across PCs, Macs, phones and tablets;
- the desktop apps Word, Excel, PowerPoint, Outlook and OneNote;
- Copilot in the apps, with a monthly allowance of AI credits (added in January 2025);
- Microsoft Defender security features.
In the US, Microsoft 365 Personal costs $99.99 a year or $9.99 a month on Microsoft’s site. A prepaid 1-year product key gives you the same plan without a monthly charge.
How to add more time with another Microsoft 365 key
You can use a new product key to extend your subscription before it ends. Redeem it at microsoft365.com/setup with the same Microsoft account, exactly as above. Microsoft explains the rules on its renewal page:
- each extra key adds time to your existing subscription;
- you can extend Microsoft 365 for a maximum of five years;
- more keys do not add more installations or more OneDrive storage, only more time.
So if you redeem two 1-year keys, you get two years of Microsoft 365 Personal on the same account, not two separate subscriptions. Tip: after each key, note the new end date shown in Services & subscriptions, so you know when to add the next one.
How to install Microsoft 365 on a phone or tablet
Microsoft 365 also works on phones and tablets. Install Word, Excel, PowerPoint or the Microsoft 365 Copilot app from the App Store or Google Play, open it and sign in with the same Microsoft account you used to redeem your key. Your subscription is recognised automatically, and the files you save to OneDrive appear on all your devices. You can be signed in on five devices at once: see how many devices can use Microsoft 365.
How to check when your subscription ends
Sign in at account.microsoft.com and open Services & subscriptions. There you see your Microsoft 365 plan, the date it renews or ends, and whether recurring billing is on. Check this page after you redeem a new key: the end date should move forward by the length of the key.
What happens when Microsoft 365 expires?
If you do not renew, your account goes back to a free Microsoft account. You do not lose your data straight away, but Microsoft explains what changes:
- the Office apps switch to reduced functionality: you can open and print documents, but you cannot create, edit or save them;
- your OneDrive storage goes back to the free 5 GB;
- if you use more than 5 GB, you cannot upload or sync new files, and after a few months Microsoft may freeze and later delete your OneDrive files.
To avoid this, redeem a new key before the end date, or download your files and bring your OneDrive below 5 GB.
Can you share Microsoft 365 Personal?
No. Microsoft 365 Personal is for one person, who can use it on up to five of their own devices. If several people in your home need Office and storage, Microsoft 365 Family covers up to six people, each with their own account. Copilot in the apps is for the subscription owner only. See Microsoft 365 Personal vs Family for the full comparison.
Microsoft 365 Personal or Office 2021?
Microsoft 365 is a subscription: you always get the latest version of the apps, 1 TB of storage and Copilot for as long as it is active. Office 2021 was a one-time purchase of the 2021 apps for one computer, without the cloud storage or Copilot.
Important: Microsoft ended support for Office 2021 on 13 October 2026. The apps still open, but Microsoft no longer releases security updates for them and recommends upgrading (Microsoft: end of support for Office 2021). If you want apps that keep getting updates, Microsoft 365 is the safer choice. If you prefer a one-time purchase, Microsoft’s current version is Office 2024.
Microsoft 365 product key not working?
- “This product key has already been used.” A key can only be redeemed once. If you redeemed it before, you do not need it again: install from Services & subscriptions.
- Wrong account. Check that you are signed in with the Microsoft account you want to use before you enter the key.
- Typos. Type the 25 characters carefully. Letters and numbers that look alike, such as O and 0 or B and 8, are easy to mix up.
- Business keys. Keys for business plans are entered in the Microsoft 365 admin center, not at microsoft365.com/setup (Microsoft Learn).
- Five-year limit. If your subscription already runs close to five years ahead, wait before you add another key.
If the problem continues, contact Microsoft Support. If you bought your key from IQSIX, message us on WhatsApp with a screenshot first, and we will help you.
Buy a Microsoft 365 Personal key from IQSIX
IQSIX sells a 1-year Microsoft 365 Personal key for PC and Mac. You get the 25-character key by email after your payment is confirmed, and you redeem it at microsoft365.com/setup with the steps above.
- Delivery: by email after your payment is confirmed (or on WhatsApp if you ask).
- Payment: crypto, card, or a Remitly bank or mobile money transfer at checkout.
- No monthly charge: one payment for one year.
- Help: we help you redeem and install on WhatsApp or through our contact page.
Setting up a new PC? Read how to activate Windows 11 Pro or see all our software keys.
Microsoft 365 product key FAQ
Where do I enter my Microsoft 365 product key?
Go to microsoft365.com/setup, sign in with your Microsoft account, enter the 25-character key and choose your country and language. Then install the apps from Services & subscriptions in your Microsoft account.
Do I need the product key to install Microsoft 365 again?
No. A key can only be redeemed once. After that, the subscription is linked to your Microsoft account, and you install the apps from the Services & subscriptions page.
Can I add a new key to my existing Microsoft 365 subscription?
Yes. Redeem the new key at microsoft365.com/setup with the same Microsoft account. Each key adds time, up to a maximum of five years.
How many devices can use Microsoft 365 Personal?
You can be signed in on up to five devices at the same time, including PCs, Macs, phones and tablets. The plan is for one person.
Is Copilot included in Microsoft 365 Personal?
Yes. Since January 2025 Microsoft 365 Personal includes Copilot in Word, Excel, PowerPoint, Outlook and OneNote, with a monthly allowance of AI credits for the subscription owner.
Is Office 2021 still supported?
No. Microsoft ended support for Office 2021 on 13 October 2026. The apps still work, but they no longer get security updates, so Microsoft recommends moving to a supported version such as Microsoft 365.
Sources, checked 17 October 2026: Microsoft Support: setup.office.com help, How to renew Microsoft 365, Microsoft 365 Personal and End of support for Office 2021. Plans and prices can change.
