To renew or extend your Microsoft 365 Family or Personal subscription with a product key, follow this guide:
Go to office.com/myaccount and sign in with your Microsoft Account
This will require your email, phone number or Skype account plus your password
Select Manage tab
Under Payment settings, you will see Have a prepaid card or code for Microsoft 365 family, select Redeem a card or code
This redirects you to Let’s get your Office where you will need to sign in with your Microsoft account, click on Sign in
Which should then only require your password, then click Sign in again
Now you can put in the product key you have be supplied and select Next
You will then need to select Country and Language, then click 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 and then select Add Payment Method
Otherwise, if you do not want to use a credit card, click on the Recurring billing tab which will then change to Off and then click on Confirm
Select Next to complete the process which will then return you to your Microsoft 365 Family page
For further information, you can also go to the following website link: Microsoft renew with a product key link
NOTE: The subscription is added to the expiry date, not from the date you renew it on
NOTE: Also, you can downgrade from a Home to Personal subscription or vice versa
