can I place an email signup dialog box in the body of a blog post?

can I place an email signup dialog box in the body of a blog post? And in the body of a static page?
I’d like to be able to have people be able to sign up right by the text that invites them to do that.
also, can I add this dialog box to the bottom of every post, as a default?
I’m using mailchimp, but I’m hoping this is not provider specific.