The 12 Bar Blues in the key of F contains the chords F7 (I chord), Bb7 (IV chord) and C7 (V) chord. Below is the 12 Bar Blues starting on F7.
12 Bar Blues in F (Jazz Variation)
The Jazz variation of the 12 Bar Blues in F adds some extra chords. The 12 Bar Blues structure remains the same, but certain chords are substituted. For example, the F7 chord in the fourth bar is substituted with a Cm7 moving to an F7 chord.