Am6

Hi, can someone explain why the Am6 chord is made up of the notes A, C, E, F# instead of A, C, E and F? My confusion arises when I understand that, in the A Minor Natural Scale, the F is natural. Why is it that when we use the chord symbol, the 6th becomes #?

Hi: broadly, if the chord had F instead of F#, such an F would be at odds with E: the interval between E and F, that is either E-F or F-E is a MINOR 2nd interval (that is, a SEMITONE), which is highly dissonant, in contrast with E-F#, a MAJOR 2nd interval, which, though technically is a dissonance, is far less dissonant than the former. Greetings