Hi there REKT222,
It's important that all your transactions are entered correctly for your books to be well balanced. QuickBooks Online is a great tool able to help you keep track of sales tax on purchases and sales so you know the amount owed to the government. I can point you in the right direction for information about marking your taxes as filed and paid.
In order to mark your taxes as filed, then as paid in your books, I recommend following the steps in this article outlining the sales tax process in QuickBooks Online.
If you have any other questions, feel free to reach out here.