We know that in certain cases ,Reverse Charge is applicable and Person Receiving goods and services have to deposit GST to Government
In this case, person depositing GST have to issue Payment Voucher to Vendor/Supplier
Example
A Provides advocate Service to B of 100000
As per GST Rule, B has to deposit 18000 directly to government under Reverse charge
Also B has to pay A 100000 (invoice amt)
So in this case, B will issue A Payment Voucher