Line-in audio


I’m building a project for the Pi (probably using an old Pi 2 B) to help digitise old music, so it’ll be taking a line-level input from, say, a tape player. Is there a good, simple device with decent quality you’d recommend for this?
For example, mentions there is no gain for passive mics - does that mean it’s taking line-level inputs, or can be set to that sort of level in software?