Here are some common questions about licensing and Copilot for Microsoft 365 apps.
It can take up to 72 hours for the background refresh of your license to take effect. Assuming you have a Copilot license, you can force a refresh with these steps:
In Word, go to File > Account.
Select Update License.
Most likely, you are signed into your desktop app with multiple accounts (e.g., a corporate account and a personal MSA account). Copilot will only work on the document that belongs to, or is shared to, the account that has the Copilot license.
Example scenario: Your corporate account has a Copilot license through your company, but you are also signed into Word with your personal MSA Account. Thus, when you open a document from your personal drive, Copilot will not be available for that document.