I want to avoid emails to customers that say “mg.paperform.co or on behalf of Paperform”. The only solution is to send campaign via newsletter services.
How about allow the use of SMTP service like WP Mail SMTP or Sendinblue.com? Information collected still stays at Paperform.co. SendInBlue.com is only used to send email out.
Ninja forms and several other online forms offer this approach. It’s simple and cost effective.