Basic Options

Preview Only
Ignore songs previously checked that could not be matched
For songs already matched
Update Artwork
Update Genres
Update Mood and other acoustic attributes such as BPM (Pro only)
Only allow match if all songs in grouping match to one album
Only allow match if all tracks in album were matched
Save changes to iTunes (or Apple Music App)

Basic Options, these are the options that you are most likely want to change.