Ninja Forms is a popular WordPress form plugin. It however does not integrate with a lot of email marketing software and CRM.
With MailOptin, you can automatically save or sync all contacts, leads and subscribers from Ninja Forms to Facebook Custom Audience with absolutely zero coding experience. The only limit is your own imagination.
MailOptin also integrates with many popular email marketing software, CRMs, analytics, social networks & WordPress solutions
MailOptin converts visitors to leads and constantly keep your list subscribers engaged with email automation.