It’s my understanding that individuals can register as media with Disney. They fill out information about their company, channel, publication etc… Once approved they are on a general list that gets notifications of minor events and they can sign up for one of the available slots. The big events are invite only. They will also occasionally reach out to very popular vloggers/bloggers and invite them even if they aren’t registered like they did on the Wish cruises. The ultimate top tier is personalized all expense paid trips like the Trackers had in California and the Bucket List Family staying a month at WDW.