Hello BigTick,
Welcome back to the Community. QuickBooks offers a variety of features that help you streamline your accounting. I'll be happy to share info and steer you in the right direction.
In order to set up your sales tax properly, I encourage you to check out this article here that shows you how to do that. Once you've set up the taxes, you can then add it your sales forms with ease. For steps on how to delete transactions, check out the following resource on how to: Void or delete transactions in QuickBooks Online.
You're welcome to ask other questions. I'm here to help.
