I need to set up my invoices to go out online and receive the payments online. i purchase the payment system from QB 3 days ago

For your reference

https://quickbooks.intuit.com/learn-support/en-us/process-credit-card-payments/sign-up-for-quickbook...

As a backup option, you should open a MP account as well

https:// melio.grsm.io/quickbooks

Welcome to the Community, @userdgstaple. I'd be glad to share with you some details about signing up for QuickBooks Payments.

When you sign up for QuickBooks Payments in QuickBooks Online, you also sign up for a QuickBooks Cash account. The signup process for both features is the same.

You'll also want to learn about this process by reading through this help article: Learn more about QuickBooks Cash accounts and the Cash Flow menu. It also gives you more insights and answers to most of your questions about QuickBooks Online Payments. 

Additionally, your payments account will automatically connect to your QuickBooks Online account. You also want to contact our QuickBooks Payments team to follow up on your enrollment through chat. 

Here's how: 

1. Click this link: https://help.quickbooks.intuit.com/en/contact.
2. Enter your concern in the Tell us more about your question field, then click Search. 
3. Click the Start a Message button, then enter all your details in the pop-up window on your left corner. 
4. Check the box for I'm not a robot. 
5. Then, hit Submit. 

For future reference, read through this article to learn more about how to let your customers pay their invoices online: Take and process payments in QuickBooks Online.

Thanks for visiting the Community, @userdgstaple. I'll always be here if you have more questions about QuickBooks. Have a great day ahead.