Add a newsletter subscription box in footer of a third part theme

[ckong]

I'm using a third party theme for a few years now and I'm pretty pleased with it. I did have a newsletter subscription box, but it only works with a Mailchimp account. And because I wasn't satiesfied with Mailchimp any longer, I ended my Mailchimp account and obviously the newsletter subscription box didn't work any longer. So I disabled it for the time being.

I don't want to install another third party newsletter app because I actually use Shopify's own e-mail marketing tool and customers can of course subscribe during the order process, but website visitors at the moment not, which I dislike.

Is it possible to add a newsletter subscription box that works together with Shopify e-mail subscription and marketing tool? If so, how?