hatstead • Adobe Community Professional, Aug 25, 2020
Each version of the program is independent and you can remove the older version if you elect to do so.
I would deactivate prior to uninstalling.
If you utilize the organizer, this will require attention.
Note that it has been reported that Adobe will market a new version of the software this fall.
Be aware that you can only pass 2019 to your daughter if you buy a full new version of 2020 - or 2021.
If you buy the upgrade version then that upgrade serial number is tied to the 2019 serial number. Every time you re-install 2020 (or 2021), the installer will also ask you to enter your 2019 serial number.
In other words, when you buy a full new version, you buy a new license. When you buy an upgrade version then you're extending your existing license so you cannot pass on your earlier version.