In order to accept credit cards online, you will need an account with Stripe. The easiest way to set this up is from the Configuration screen.
Click Registration, then choose Configuration
Click Connect with Stripe to get started.
You'll be taken to the Stripe website. If you have a Stripe account, use the link at the top of the page. Otherwise, fill out the information on the page to get started.
Stripe may show you a screen asking for permission for assignr.com to access your Stripe account. If you see this screen, click the Connect my Stripe account button
Once you have granted permission for assignr.com to process credit card transactions on your behalf, you'll be returned to the assignr.com website. On the Configuration screen, you will see that credit card transactions are now enabled: