Major 7th Chords
Here are the main major chord shapes you can play on the guitar:
Root 6 (Tonic on the 6th String)
Root 5 (Tonic on the 5th String)
Root 4 (Tonic on the 4th String)
There are other major type chords with can often also be used like 6, maj 9, 6/9 etc depending on the type of voicing that you are looking for.
Major 7th chords are great when used in Bossa Novas as well flamenco style Rumbas.
You can find more Chord Diagrams in the free E-Book you get when you subscribe to LGM.