The easiest way to embed a subscribe form in the Mashshare subscribe slide down box is to use a third party mailing plugin like “mailpoet” or contact form plugin like “contact form 7 (cf7)” and copy its integrated shortcodes into the Mashshare settings field for the subscribe button.
If you are using “mailpoet” this is an example code borrowed from mashshare.net including a Facebook like button.
You have to adapt this to your needs:
<div class="email-subscription"><strong class="title">Sign up and we notify you about new features and Add-Ons</strong>[ wysija_form id="1" ]<span class="note" style="font-size: 12px;">We promise not to spam you and not to give away your mail address. Read our <a href="/privacy">privacy policy</a>.</span></div> <div> <div style="float: left; padding-right: 10px; margin-top: 4px;"><strong class="title">Don't forget to like Mashshare: </strong></div> <div style="margin-top: 10px;"><iframe style="border: none; overflow: hidden; width: 90px; height: 21px;" src="//www.facebook.com/plugins/like.php?href=https%3A%2F%2F.facebook.com%2Fmashshare.net&width=90&layout=button_count&action=like&show_faces=true&share=false&height=21&appId=317697668417910" width="300" height="150" frameborder="0" scrolling="no"></iframe> <iframe style="width: 200px; height: 21px;" src="//platform.twitter.com/widgets/follow_button.html?screen_name=mashshare&lang=en&show_count=true" width="300" height="150" frameborder="0" scrolling="no"></iframe></div> </div>