There is a wide variety of guitars available throughout the world. Most guitars are a standardized to 6-strings and while other tunings are available the standard turning for a 6-string guitar is e – b – G – D – A – E (with ‘e’ being the first/highest string and ‘E’ being the last/lowest string).
The written range for a standardized guitar starts at the ‘E’ below Middle C and can go up to the B an octave above the staff. This range can be extended by the use of harmonics. The sounding range of a guitar is an octave lower.