Use a Spend Money transaction from a cash account. Allocate the transaction to Tax payable. The liability in Tax payable will decrease by the amount of your payment. Depending on the pace of your business, the balance in that account at year end may equal what you should remit. But if there was a balance carried forward from the previous year, that won’t be the case. And if you have collected sales tax this year, it also won’t be true.
Some creative filtering and date setting in the various tax reports should produce your amount due, however. Of course, another alternative (or double-check, depending on how you look at it) is to post all taxable sales to a designated income account. Then, the amount of taxable income is another cue to what you owe.
You may also have county and municipal taxes, though, which are not very well handled by Manager. See the Guide: https://www.manager.io/guides/best-practices/multi-component-custom-tax-codes.