You can accept payments from your customers in three different ways.
You can receive payments by sending Drafts with Simple Invoice, adding a payment link to the “My Account” Page, and sending Quotes to your customers.
You can get more information for each option from the guides below.
Sending Drafts: https://support.simplio.app/knowledgebase/how-can-i-receive-payments/
My Account Page Payment Link: https://support.simplio.app/knowledgebase/how-can-my-customers-pay-the-remaining-balance-of-their-orders-from-the-my-account-section-of-my-store/
Creating & Sending Quotes: https://support.simplio.app/knowledgebase/how-can-i-send-invoices-or-quotes-and-accept-payments-from-my-customers/