Moving my domain hosting from Bluehost to Heroku

I registered and hosted a new domain with Bluehost because I thought it would be a simple WordPress site. Since then, I have instead created a custom MERN stack application. I understand that Heroku isn't a registrar, so I will have to leave that with Bluehost or move it somewhere else, but I would like to move the hosting of my website to a paid Heroku account, so I can maintain the URL. So far I have nothing but a temporary holding page on Bluehost, so no need to preserve anything. Could someone help me with the process of moving the domain hosting from Bluehost to paid Heroku? Thanks!