Barre chord
fret 1, A shapex13231
B♭maj7 is the B♭ major 7 chord. Its notes are B♭, D, F and A. It is the same chord as A♯maj7. An open, reflective color. The major seventh sits a semitone below the root.
x13231
687766
Numbers show frets from the low E string to the high e string; x means don't play that string.
B♭maj7 is the Imaj7 chord in B♭ major and the IVmaj7 chord in F major. That makes it a natural fit in songs written in those keys.
Every B♭, D, F and A on the first 12 frets. The filled dots are the root, B♭. Build your own shape from any nearby group.
Other B♭ chords
Other major 7 chords