How do I print Sales Tax payment voucher for backup record in new QuickBooks Online?

They do not have a standard Sales Tax payment voucher to print at this time.

Best you can do is to print Sales Tax Payment statement.

From the home page screen

  • Select “Search” (magnifying glass, upper-middle next to plus sign)
  • Select Advanced Search
  • Select “Sales Tax Payments” as search setting from drop-down selector
  • Select “Account” or “Date”
  • Select “Search” blue button
  • Select “Print” icon (located at far right middle section)

See screenshot photo for reference

Sales Tax Payments
Sales Tax Payments