If you have the need to bill clients on a scheduled interval for a preset amount, you have two main options:

1) You can use Recurring Profiles to achieve this goal, if the end result is to send the client a new invoice on a set schedule, where the client would pay each invoice manually. This function allows you to create a single invoice “Profile”, and fill that Profile with any items, taxes, and discounts that you would like. Once the Profile has the desired total, you can set the timeframe for the subsequent invoices (weekly, monthly, yearly, etc), as well as a duration period (6 months, 12 months, etc). After that, simply assign the Profile to a client and/or Circle, and save. Once saved, the Recurring Profile will start to go to work. A new invoice will be created according to the previously defined timeframe, and that invoice will automatically be filled with the items, discounts, and taxes that you set in the original Recurring Profile. Each new invoice will be visible to the client in their dashboard, and they will be able to make payment just like a normal invoice.
You can read more about Recurring Profiles HERE

2) Alternatively, you can add Recurring Plans (from Braintree or Stripe) to a normal Invoice, to automatically charge clients on a recurring subscription basis. When using Plans, you will setup the initial subscription plan through either Stripe or Braintree (with the option to create Stripe plans directly inside SuiteDash), including setting the price and frequency. The clients will pay the initial Invoice payment as normal, after which their payment credentials will be captured, and they will be automatically charged based on the price and frequency of the Plan you set.

You can read more about Recurring Plans HERE