Install

I appreciate your time in posting your concern here in the Community, tcberry22.

Yes, the transactions will still be available after deleting a certain project. I'd be happy to discuss this in detail. They'll remain under the project, and there's a (deleted) mark next to the customer's name, and it can't be reverted.

Here's a sample screenshot for your reference:

Also, you can refer to this link on how to add customers: Add and manage customers in QuickBooks Online.

Additionally, I've included an article that'll help you learn how to set up and manage projects in QuickBooks: Create and manage projects in QuickBooks Online.

Feel free to comment below if you have concerns or questions about customer transactions. We're here to help you. Take care.