Notes that have the same pitch and position on the fretboard but a different note name is what we call an enharmonic equivalent.

These are very common when you are looking at a scale that has sharps and flats with the same position and sound.

When you are writing out your scales and you see a note like Gb for example that is the same note and position as F#.

The circle of fifths is also a great way to view enharmonic equivalents visually. To learn more about the circle of fifths check out my video here.

G♭ Major Scale: G♭ – A♭ – B♭ – C♭ – D♭ – E♭ – F♭ – G♭
F# Major: F# – G# – A# – B – C# – D# – E# – F#
D♭ Major: D♭ (C#) – E♭ (D#) – F – G♭ – A♭ – B♭ – C – D♭ (C#)
B Major: B – C#(D♭) – D – E – F# (G♭) – G# (A♭) – A# (B♭) – B

Enharmonic Equivalent Notes (for any scale):
Ab/G#
A#/Bb
Bb/A#
B#/C (natural)
Cb/B (natural)
C#/Db
Db/C#
D#/Eb
Eb/D#
E#/F (natural)
Fb/E (natural)
F#/Gb
Gb/F#
G#/Ab