The maj13 is also named major thirteenth
Use Maj13 instead of maj13
Use ^13 instead of maj13
A maj13 is a Major chord
How to construct a maj13 chord?
Use the following intervals in any order to construct this chord. Start on a specific note on which you want to construct this chord from (for instance the note "C") and calculate each interval on top of it. Afterwards, you will be able to play it on your instrument.