Most term life plans are level term life insurance which means the amount of life insurance coverage provided by your policy will remain the same throughout the entire herm (duration) of your coverage.
In addition, the premiums you pay stay level each year for the term of your coverage.
So, if you have a 15 year level term policy with $100,000 of coverage at an annual premium of $200:
You would pay $200 each year you are insured for 15 years, and have $100,000 of life insurance for a period of 15 years.
Decreasing term life insurance policies require level premiums be paid each year for an amount of life insurance that decreases each year until your term ends. These plans are used most often for protection on short term loans; such as, mortgage loans on your home.