Draw LENGTH on some bows is adjustable in 1/4" incriments. Some bows like Mathews and some Martins require a whole new cam to change length. Other bows use what is called a " module" to change draw length.

Draw weight is adjusted by the limb bolts. They should be turned in equal amounts. Most bows have a 10# weight range, others..15#.

Arrow length. Modern bows have cut away risers that allow most broadheads to be drawn back beyond the front of the bow. I prefer not to do it unless using a rest that protects my hand in some way. On my bow I have a 29" draw length. Arrows that come out even with the front of my riser are 30" long. However, my rest allows me to shoot arrows as short as 28" (which I do) because it supports the arrow behind the riser.