I have 2 cracks in my wall that are about 1/4 in. wide and 3ft. Long. I called a contractor out and he told me that the cracks were not from the foundation. How can I repair these cracks myself

Plaster or drywall? I have never seen a 1/4" crack wasn't related to settling and foundation issues. Answer my question and we can go from there

The cracks are in the drywall and yes the foundation is settling

Makes the contractor so wrong that I would not use him. You can patch drywall but if the findation continues to move the crack will return in the same spot. Cracks are most frequently at door frames and window opening running diagonally away from the frame. Rough the area with sand paper and then apply fiber mess drywall tape or a larger version made for cracks. Then apply a thin coat of dry mix joint compound, not the light, pre-mixed stuff in a tub. Two more coats each one larger than the last to feather out the thickness of the patch with light sanding of each coat. Prime and repaint.

Bob is correct that without fixing the foundation problem the cracks will return. You can repair them and if you need a texture you can buy orange peel in a can from home depot or Lowe's and apply according to directions.