1. If your music is in the Finder's Music folder, then set the display of that folder to List view (View menu) then do a right-click (or CTRL-click) on the title row. You can choose several other attributes to display.
Unfortunately Bit-rate is not on the list!
2. Select any music file in the Finder and choose Get Info from the File menu. Bit rate and other attributes of the file are shown there.
3. In any Finder window set the view to Gallery (View menu) then the attributes of the file, including bit-rate if a music file, will be shown on the right.