How can I stop people from going to my online forms and using them for sending out spam?

Answer 1

Add a verification script. You know when you fill in a form and you have to copy the letters or numbers into a box - that type of thing. It's called Captcha.

You're getting spam because programs are finding your online form and automatically filling it in, the idea of a verification script is that a machine can't read it so the form has to be filled in by a human.

Answer 2

choose a more secure script.

if your online forms allow anyone to post anything easily then a software program running on a spammer's computer will easily post spam on your site automatically for as long as you let it.