E invoicing of march

In march...........................

The invoice will get reflected in GSTR 1 of April 2022 because you generated the E-invoices in April 2022

As per my experience, any IRN generated against any invoice in current month only reflecting in Current Month's GSTR 1. Any IRN generated for previous months are not reflecting any where, In this situation we are entering manually.

E-invoices are auto-populated if those have been generated before your GSTR-1 filing. And the invoice will appear in the month of invoice date, whether you generate it in the following months.