Different call to actions no head


I´m new here, so forgive me if I make a stupid question.

I would like to have different call to actions on my blog posts.

For example: usually I would like to have a subscription box on top of my post, like these one - https://snipboard.io/GJ97oC.jpg, but sometimes I may need to have a call to action button, because my company can be in some kind of launch.

Is there a way to do that? Maybe partials files?
If yes, once the partials.hbs files were created, could I change them from the admin panel?

Thanks in advance