Invoicing electronically

zoho experts,

I have a friend who has a chemical distribution business.

I'm trying to help him using zoho.

He is telling me as per regulations, he cannot generate email on his computer , print it and send it to his clients.

He tells me, he needs to get special permission from authorities, use a dot matrix printer with a running sheet to generate invoices using computer.

I find this odd and hard to believe.

Can he not use zoho, create invoices, print it and mail/fax it to his clients ?

Any pointers on what the regulations show ?

Thanks
PV