Manual Approval for Paid Member (Charge once Approved)

Hi everyone.
I want to have a manual approval for new members. As in at sign up, Stripe details will be taken. They will then go through an internal voting system (using an API). If approved, they are charged on Stripe and upgrade their status to Paid and get the paid privelges. (In this case, an invite to Slack - we can do it via API).
My current tech stack is with airtable.
How can I do this in Ghost?