Some plans offer the option of a monthly commitment (paid monthly) or an annual commitment (paid monthly or annually). Adobe offers a lower price to users who commit membership for a full year at a time. The monthly payments are lower than the monthly plan, but there is a penalty for early cancellation, so if you wish to become a member for a few months, you should purchase the monthly plan. If you are willing to commit to a full year of membership, you will save money selecting an annual plan. Membership plans renew automatically until they are cancelled.
You can find the different Creative Cloud plans here: Membership Plans
You can see answers to other frequently asked Creative Cloud questions here: