It is possible to manually add a payment plan in the backend dashboard.

There are a few options to do this:

1. User Switching Plugin (the easier option, in our opinion)

Do you have the customer’s credit card information? If so, I would recommend installing the User Switching plugin and then do the following steps:

• Create the customer in WooCommerce and then ‘switch to’ that user.
• Add product and payment plan option to Cart
• Go through checkout process impersonating that customer
• Enter their cc info on Checkout
• Place Order

Here is more info on manually adding customer and using the User Switching plugin (skip to 4:04 if you just want to learn about the User Switching plugin):

2. Manually add payment plan

• Create a new order (this will be the parent order)
• Create a new Payment Plan (assign parent order as 1st order in Payment Plan)

If your customer has already been a customer in Stripe and has a saved token, you can get their Stripe Customer ID and Stripe Source ID in Stripe’s dashboard.

Just search the customer and find their Customer ID and Stripe ID in the dashboard and paste into the Deposit.