There are various types of opt-in forms you can use:
Pop-ups: These appear in a separate window over the main content and grab immediate attention. Inline Forms: These are embedded within the content and flow naturally within the page layout. Slide-ins: These forms slide in from the side of the page and are less intrusive than pop-ups. Exit-Intent Forms: These appear when a user is about to leave the page, giving you one last chance to capture their information.