Hello,

1. Create a menu Appearance > Menu > Add a custom link with # http://prntscr.com/jq01oo

2. Add class woodmart-open-newsletter to the menu item as shown: http://prntscr.com/jq01gt

3. Navigate to WooDmart > Header builder and add a Secondary menu http://prntscr.com/jq0360

4. Make sure the promo popup has been activated in Theme Settings > Shop > Promo poup

You will find the filed for content. Also, you can insert there HTML block. Please find here instructions for HTMl blocks https://xtemos.com/docs/woodmart/html-blocks-2/

Best Regards