Good Day, I have High TSH result 20.5 and hypothyroidism, What is the treatment to make it normal? Thanks a lot.

Thyroxine. Please see your doctor as you need a prescription for the thyroid replacement medication.
For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form.
Practice safe sex, if you have sex.
Get HPV vaccine.