Here are some Major 7 Inversions. I go through examples on the 6-2 strings, 5-2 strings and 4-1 strings. Major 7ths are built with 1-3-5-7, in our example of F the notes would be F-A-C-E.
Root position – Root note is bass note
First Inversion – 3rd is bass note
Second Inversion – 5th is bass note
Third Inversion – 7th is bass note
Let me know if you have any questions!