Navigate to the member's profile  -  and review the associated user account primary profile (that's the name of the purchaser on the receipt)

If you click "View" on the receipt under the Generated Documents section, you'll be able to review the current purchaser name on the receipt

See 'purchaser name' in the right side column of the table

Click on the user account name to access the user account details

Under the PROFILES section, you can identify the primary from the "Role" column, and change the selection as needed.

If the purchaser's profile doesn't exist yet, click "Add person" to create it

Click "Primary" on the newly created profile to make is 'the purchaser'

Go back to the member's profile you need to update the receipt for, and scroll down to the Generated Documents section

Click "Generate" to regenerate a new receipt with the updated purchaser's name

Click "View" to make sure the purchaser's name was properly updated

Annual Custom Tax Receipt for club activities: How to update the purchaser's name?