How do I enter 2 years of PST returns into Quick books that have already been paid but not entered?

Hello there, @breezethru.

You have two options to enter two years of PST returns in QuickBooks Online (QBO). And I'd be glad to help you out with this.

Since QBO calculates PST automatically, you can enter each transaction to a sales or an expense transaction. You also have the option to create a journal entry for the total amount of transactions month by month.

If you happen to have each transaction, you can create a sales or an expense transaction, like Invoices, Expenses, and Cheques.

However, if don't want to enter each of the transactions, you can create a journal entry. And when entering journal entry, select the associated account and enter the total amount of the transactions month by month.

You can check out this article for your reference: Create a Journal Entry.

In case you need tips and related articles in the future, visit our QuickBooks Community help website for reference: QBO Self-help.    

Please feel free to post any questions you have below. The Community is always here to help out.