Verify your site.
You tell us the domain, what the site is about, roughly how much traffic it gets and where the readers are. It takes a couple of minutes. We ask for an analytics screenshot because it is the fastest way for a real site to prove it is real, and it is stored privately: no advertiser and no other publisher ever sees it.
Then you prove you control the domain. Two ways, whichever suits your setup. Add one meta tag to your homepage, or add one line to your ads.txt file. Both prove you control the domain and neither changes anything a reader sees. There is a Check now button, so you are not waiting on a cron to find out whether it worked.
Then a person reads it. We are looking at whether the content is real, whether the traffic looks like people rather than a purchase, and whether an advertiser would be comfortable appearing next to it. Decision within 48 hours. If it is no, you get the actual reason and can fix it and resubmit.