Subscription plans allow customers to sign up for access to your content that's invoiced on a frequency you set. It's a good idea to have a few plans available. Monthly and Yearly plans are the most common plans.
You can read more about setting up tiered subscriptions here.
A Couple of Subscription Tips
When titling your subscription just keep in mind how you want it to appear in contrast to your other subscription plans. Make sure the titles are consistent, don't do this:
7 day sub
Thirty Day Subscription
3 month plan
Your customers will see all available subscription plans when signing up so it's important they have coherence, which builds trust with your customers.
You probably want customers purchasing yearly plans so if you're creating the plan that you want customers to purchase most, put a little bit of extra flair into the thumbnail and description.
Thumbnails that show savings are highly recommended: