Hello Tim OConnor,
Thank you for posting in Q&A forum.
Based on your description, in order to add a second account to Win 11 Pro pc, please follow these steps:
Click on the Start menu and select "Settings"-->Accounts" and then select "Access work or school".
Next to “Add a work or school account”, select “Connect” and enter your work email address (Enter that person's account info, select the account type, and then select Add.)
If you've done that, you'll be able to log in with this account.
For extra reference kindly refer to link below: https://support.microsoft.com/en-us/windows/add-or-remove-accounts-on-your-pc-104dc19f-6430-4b49-6a2b-e4dbd1dcdf32
I hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards, Daisy Zhou
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