I'm glad to see you posting here in QuickBooks Community. I'll ensure that you're able to see the button for the tax payment.
There are times that the browser keeps outdated Internet files and needs to be cleared. This is done once in a while because it can cause websites to receive unusual behavior like a missing button.
I recommend logging in to your QuickBooks account using a private browser. This is to rule out the possibility of a webpage issue, and private browsing doesn't store local files or cache.
Use these keyboard shortcuts based on the browser you're using.
For Firefox or Microsoft Edge, press Ctrl + Shift + P.
For Chrome, press Ctrl + Shift + N.
For Safari, hold down Command + Shift + N.
If it works in incognito, I recommend clearing the cache of your regular browser. This removes the history or log of sites so you can start with a clean slate. You can check this article to see the steps: Clear cache and cookies to fix issues when using QuickBooks Online.
Once done, I suggest going to Sales Tax Settings and make sure that the State Agency is not deactivated. If so, you can click the small gear icon to show all inactive agencies and make them active again.