subdomains

They are completely separate sites this way. You can host the next app on vercel and the WP one on dreamhost if you wanted

@Yi Lon Ma @Asian black bear do you guys know how I could do my example? How would I make it the same domain on two different hosts

you can add a button in your landing page leading to app.domain.com

domains has a concept of subdomains

just point a new subdomain to another host(app in this case)

I think we need to be clear about what you mean by "the same domain" -- domain.com and app.domain.com are related by the suffix, but otherwise are totally independent. In your dns provider you would need to add two records, one for @ (the top level), and one for app. Beyond that they are entirely separate and do not need to know about each other at all.

Having Wordpress and Next come from www.domain.com like www.domain.com/wordpress www.domain.com/next at the same time is orders of magnitude more difficult, and what technical people assume you are talking about with "the same domain". If someone told you it was hard, this is what they thought you were saying.

@Hamiltonstövare ^ I forgot to ping you

Thank you, I got it working 🙏