
Hi @Ahmed Atif
MAK activation is used for volume licensed versions of Office, one key can be used on multiple devices to activate Office.
Each MAK has a predetermined number of allowed activations and is based on your volume licensing agreement. Each Office activation that uses MAK counts toward the activation limit. After Office is activated, no reactivation is required unless the hardware changes significantly.
If your device changes the hardware significantly, the MAK count is not enough, please request an increase to MAK activation limits from Microsoft: https://learn.microsoft.com/en-us/microsoft-365/commerce/licenses/product-keys-faq?view=o365-worldwide#how-to-request-an-increase-to-mak-activation-limits
- To check your volume licensing agreement, please refer to: https://learn.microsoft.com/en-us/licensing/
- To deploy LTSC versions of Office 2021, you may run ODT tool with configuration file (.xml), for more, you may refer to: https://learn.microsoft.com/en-us/office/ltsc/2021/deploy
- The reference of using MAK activation: https://learn.microsoft.com/en-us/office/volume-license-activation/activate-office-by-using-mak
But for retail versions of Office, the keys are different. The first thing to do is redeem the product key which means binding the Microsoft account to this key. Your product key can only be redeemed once, it can't be re-used or shared to other users. It is recommended to record the device and account information corresponding to the key.
Once you need to re-install Office, you can go directly to your Microsoft account, Services & subscriptions page with the correct Microsoft account signed in, by this way, Office will be activated automatically.
Any further issues, welcome to post back.
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