You can renew or extend your Office 365 for home subscription with a product key.
To renew Office 365 for home with a product key:
- Go to Office.com/myaccount
- Sign in to the Microsoft Account you use for Office 365
- Select the Payment & Billing tab
- Under Payment settings, you will see “Have a prepaid card or code for Office 365 Home?”, select Redeem a card or code
- This redirects you to Use your Microsoft account to get started which should still be signed in with your Microsoft account. Click Next
- Now you can put in the product key you have be supplied and you will need to set the Country and language then select Next
- You will then be prompted whether you want recurring billing or not, if you leave the tab on for recurring billing, you will be prompted for credit card details. Select Next.
- Select Next to complete the process
For further information, you can also go to the following website link: Microsoft renew with a product key link
If you have any issue renewing via your Microsoft Account page, try using this alternative redeem method instead.