Are you on a self-hosted blog?
Even if Jetpack enabled, worried about the missing follow button which appeared as plus icon at the bottom right corner of your old wordpress.com blog?
If so, have a look here Follow Button Creation.
- You can generate a WordPress.com Follow button [This wont that plus icon as in wordpress.com blogs, but a new button] for your site at https://developer.wordpress.com/docs/follow-button-creation/.
- Then add that code to your widget area [Appearance > Widgets in your site’s Dashboard using the Custom HTML widget]
This follow button will help any WordPress.com users to easily follow the specified WordPress.com or Jetpack enabled blog.