Assuming you know what you the estimates need to be based on 2020 tax return

1)Enter client information - name, address, etc

2)Go to Estimated Tax Worksheet, enter amount in PartIV, line 6

3) Print vouchers

 

Fill in their personal info on the fed info worksheet, then open the 1040ES worksheet to prepare vouchers...do you know how much you want them to be? If not, you can scroll down to Part V and enter in their estimated 2021 income/deduction info, to get the program to compute what the required estimated payment should be.

Go to www.irs.gov and do the fill-in 1040-ES.  Of course you can set up a new client in ProSeries too as alluded to by prior answers.