A Bass Clef is used on the musical staff for:

Low voices and instruments
High voices and instruments
All voices and instruments
It depends on the peice

A Bass Clef is primarily used for low voices and instruments. It is specifically designed to indicate lower pitches, and is commonly used by bass singers, lower brass and woodwind instruments, and bass guitars. However, it can also be used for higher voices and instruments in certain musical contexts or specific pieces that require transposition.