Had no idea how to phrase the question better.
My problem is, that sometimes I want to send an important notice to a company. I use normal, not electronic, mail - "recorded delivery". The problem is, that I only get evidence of sending the mail, and no confirmation about what was in the envelope - that's why I also send an e-mail, saving it in sent folder. Unfortunately some companies don't have e-mails (or they don't public e-mail addresses), only web forms.
If I understand it well, web forms work like this: user fills up input fields and clicks "send" button, browser makes a GET or POST request to server URL given in form's "action" attribute, and the PHP file at this URL is sending the message to smtp server. Can't get the e-mail address from the source, can't even get the smtp server address.
I guess that makes it impossible to use gmail to send e-mail through web form. But maybe there are other solutions to keep evidence of forms being sent?