How I can block spam e-mails?

Dear all,

some people uses my forms to send spams. How can I block those e-mail addresses?

Please help me.

Thank you very much

Lakis Toussas

You can set a limit in the form, you can use any of the following:

https://www.jotform.com/help/223-How-to-set-Form-Limits-Based-on-a-Unique-Question 

https://www.jotform.com/help/64-How-to-Set-Unique-Submissions-on-a-Form 

The unique question limit is recommended for your case.

I would also suggest adding a captcha in the form:

https://www.jotform.com/help/205-How-to-Add-a-Captcha