Don't know which Windows 11 version you have but this is the steps to add a local account (offline account) for the latest Windows 11 24H2:

• *  Open Settings: Click the Start button, then select "Settings". 
• *  Navigate to Accounts: Click on "Accounts". 
• *  Go to Family & other users: Click on "Family & other users". 
• *  Add a new account: Click on "Add account" next to "Add other user". 
• *  Select "I don't have this person's sign-in information
• *  Choose "Add a user without a Microsoft account
• *  Enter Account Details:
     *Enter a username for the new local account. 
     *Optionally, enter a password and password hint. 

   *  Click "Next" to complete the process. 

Edited to clean up text format.