Number 9 envelopes for invoice printing

Number 9 envelopes for invoice printing

I email and print invoices. Being new to Zoho and coming from QB, we did both as we have a more traditional So in Zoho i want to do the same using Number 9 envelopes. These have both a return window and mail to windoow see attached image. Im just looking for best suggestions on how to get a ZOHO invoice to work, so I can mail my invoices...