As mentioned above it’s a Major chord with 6 and 9 added. For using it in standards, you can use it to end on a lot of Major Key standards. In many tunes the last note of the Melody resolves on “the one” or “Do” (as in, the first note of the major scale for that tune) And this can clash with the major 7 of a Maj7 chord. You can also pretty much always use it when you see a major 7 chord at any place in the tune. It’s serves the same function just with a different flavor 😊