So when I'm DMing people in the early stages, oftentimes I would just say, "what's your email address?" and I would add them manually.
Eventually I set up an opt-in form and had a landing page that explained what coworking was and had all the details. I set that up on my link-in-bio page, and would sometimes send it to people in the DMs if I was feeling lazy.
In some Stories I would use a Q&A sticker that said "Drop your email here and I'll add you to the coworking list!", and then I would add them manually to Mailerlite and make sure they were properly tagged.
So there are ways to do it manually. There are ways to do it in more automated way.
The more manual ways, in the early stages are great ways to make things feel personalized. Because if you're saying, what's your email address? There are eight fewer clicks that the person has to make in order to sign up for your coworking.