If i set it higher or lower will i tune higher or lower
By way of a little more information, Mk,
Hertz (Hz) is the number of times the vibration of the string moves back and forth when you pick it.
Each note has a number.
The higher the number the higher pitch the note is.
As knight_yyz says
"440 Hz is a Standard "A" note"
(2nd fret third string)
A440 is the reference starting point most people use, and the tuner then does the math for you in each direction, high to low for each string.
If you choose to set a number on your tuner higher than 440 to tune your guitar to, your guitar would be "sharp", ie higher than most others.
If you choose a number lower than 440, your guitar would be "flat" ie lower than most others.