It depends on how high the factory or previous owner set it. On my '01 it takes 20 full turns on the adjusters to go from top to bottom, which moves the front up/down about 4 or 4.5"
So... If it was pretty much in the middle to start with, then you can raise or lower it about 2" from stock. In theory. In reality, it takes 6 extra turns on the driver side to get it to level left/rigth, so the "useful" range is just 14 turns.
To get a full 3", you can use aftermarket torsion keys, or modify the stock setup.
Will it hurt anything? If 4wd, then hell yes! 3" will destroy the CV joints. So you'd keep it under 2" - just crank em both full up, then back off the high side to level, and you'd be at the top of the safe range.
If 2wd, then you won't hurt anything, but at 3" you'll be at the top uf your suspension travel, unless you get longer shocks the ride will suck. With longer shocks you'll get more travel, but then you'll have to do some grinding for lower ball joint clearance, plus other issues like uca angle & ball joint bind when yuo lift higher.