How can I remove the previous owner of her Apple ID
I don’t have any receipt that I bought this watch as a secondhand I don’t even know the Apple ID that she use
Question marked as
You cannot remove the Activation Lock and no one, not even Apple, will do it for you. Only the original owner can remove the Lock. The Lock prevents lost and stolen watches from being used by others.
Contact her and get her to follow the web procedure to remove the Activation Lock.
How to remove Activation Lock - Apple Support
Otherwise, you bought a paperweight.
M1 Mac mini, macOS 14.1.1; Watch, series 7 GPS/cellular, watchOS 10.1.1; iPad Pro 2nd Gen, iPadOS 17.1.1; iPhone 12 Pro, iOS 17.1.1; TV 4th Gen, tvOS 17; HomePods, audioOS 17.1.1 and Airport Express w/ Airplay 2