1041 Virginia 770 letter

That stinks, but can you modify the VA 1041 letter to include the tax due?

Yes, it can be edited manually each time, but the current letter coding does not recognize that there is a balance due, so there is no way to edit the letter template to reflect a balance due.

Doesn't VA require electronic payment? Hence no voucher?

Even if that were the case, shouldn't the letter state "You have a balance due to Virginia of $xxx. Payment must be made electronically at tax.virginia.gov"  The letter does not indicate a balance is due.

It was the case for a short period of time (2017 and 2018 tax years), when a waiver was required for a fiduciary to pay other than electronically, but that changed for tax year 2019. Here is a link to the VA tax website https://www.tax.virginia.gov/fiduciary-income-tax which states:

Return Payments

If paying after you file your return, you can make an electronic return payment using the 770-PMT eForm or Web Upload. 

If you prefer to pay by mail, complete the 770-PMT voucher and send it to us with your check or money order.

You can edit and save the template.