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7th chords are major 7th chords with the 7th note a half step below the root note and the Dominate 7th chord, a whole step below the root note.
Most blues, rock, country, folk songs use the dominant 7th. Some alternate, jazz, classical and americana artist’s use the major 7th chord. I us e both in different contexts of a progression.
The dominate 7th has more of. to my ear, a dissonant tone than the major 7th chords. You definitely want to resolve to another chord to smooth out the progression.
Play a C chord on the B, G and D strings at frets B/5, G/3, D/5. that is a dominate 7th C chord
Now play the major 7th chord on string position B/5, G/4 and D/5. That is a major 7th and sounds almost “sweet’ to me. Both can be used as a transition chord to another chord, usually, for me back to the root chord for the dominate 7th chord and to the minor 6th chord from the major 7th of that key.