Finding my serial number on my 2023 Elements

It's in your Adobe account under "Plans and Payments/ products.   PSE serial numbers always begin with 1057---

Depends upon the type of licsense you purchased.   If your licsense says "Windows"  you're probably basically out of luck. If your liscens says "multiple"- under the OS Platform type- then you are good to go.

There is always debate about this.   Many users will say "But I paid good money.... blah blah blah...." and give Adobe a sob story expecting them to give them a serial number that will work on a new platform (which you have) when their orignal purchase was just for a single platform liscense.