Can also link to a MailChimp SignUp form- ie Bizboost website https://www.bizboost.com.au/ (bottom middle footer widget), this uses a MailChimp WordPress Plugin
Plugin for pop-up: Easy Forms for MailChimp by YIKES
Can also make into a pop-up: Bizboost website https://www.bizboost.com.au/web www.murraymallee.org.au/contact-us
Can schedule when pop up appears and on what page.
If you want to have certain sections of your header image that open up a pop up window with info if clicked on.
IE www.murraylandsfoodalliance.com.au (included in custom design)