I am new to this programming world. This is a self-picked project I am working on. I wanted to develop a form that would take input from the sales agents and then send the invoice to the customer with a payment link or payment option.
The customer would then be able to pay the invoice. I want to connect the stripe and PayPal option. I have the front end of the form ready. The question is, what will be the next step in this process? Do I have to create a database? Or if someone can guide me?
Please understand that this is not a checkout. This is just to avoid giving access to the stripe or PayPal dashboard to any other person.

Any advice will be appreciated

Thanks in advance.
Noob Programmer