I have version 2.0.0 Is it possible to change key signature of song imported?
You CAN change the key/pitch of the entire piece: Effect Change Pitch.
I just looked-up [u]Key Signature[/u] because I wasn’t sure what it means. No, you can’t change the “key signature”, but I assume you just want to change/transpose the key.
FYI - If it’s a small change and you can live with a corresponding tempo change, the Change Speed effect is mathematically simpler and less prone to artifacts (side effects).
“Change Pitch” will do exactly what you want. Select the whole piece, and put in the old key then the new key (keys work as well as notes). Be aware that if you change it a whole bunch (like up a fifth) the voicings may sound strange from a musical standpoint.
I strongly suggest you upgrade to the latest 2.0.5 from Audacity ® | Download for Windows unless you have a reason to retain 2.0.0.
The latest version will always have the latest features and fixes.
Gale