It is a very simple thing to pray for healing. Just say:
Father, I am Your child. I am filled with Your Spirit. I believe that Jesus bore my sickness and carried my diseases, and I believe that by His stripes I was healed 2,000 years ago.
Right now, I accept that fact by faith. I believe that I am healed now, in the Name of Jesus.
As a child of God, you have the right to command Satan to get out of your life. He has no right to lay sickness of disease on your body, because Jesus bore all sickness and disease on His body. For Satan to put any of that on you would be a miscarriage of justice. You are God's property and Satan is a trespasser. He has no right to touch your spirit, your soul or your body.