How do I change my Apple ID password?

See Change your Apple ID password https://support.apple.com/en-us/HT201355 

Here is What to do after you change your Apple ID or password https://support.apple.com/en-us/HT204071

Manage Your Apple ID -

https://appleid.apple.com/

ASC - Late 2012 Mac mini, macOS 10.15.4; Watch, series 5 GPS/cellular, watchOS 6.2; iPad Air 2, ipadOS 13.4.1; iPhone 8+, iOS 13.4.1; TV 4th Gen, tvOS 13.4;  HomePods, audioOS 13.4 and Airport Express w/ Airplay 2