The shift away from traditional serial numbers and authorization codes towards a subscription-based model offers several benefits:

You do not need a serial number. Simply sign in with your email address in SketchUp Pro 2022, and the license will activate automatically.

When a classic license was purchased or upgraded, SketchUp sent an email containing the licensing details. Search your inbox for "SketchUp License Information" or emails from @sketchup.com . 2. Use the Online License Manager