Is the password for "user" my apple id?
is my "user" password different from my apple id and what might it consist of? how many letters numbers etc?
MacBook Pro 16″, macOS 10.15
Your Mac user account is your login user name to Mac.
and what might it consist of?
Only you know that, you have set the password for Mac login.
See -> If you forgot your Mac login password -> https://support.apple.com/en-us/HT202860
See also ⤵️
Change the login password on Mac
https://support.apple.com/en-gb/guide/mac-help/mchlp1550/mac
Reset your Mac login password
https://support.apple.com/en-mn/guide/mac-help/mh35902/mac
If you can't reset your Mac login password
https://support.apple.com/en-gb/HT212190