I really thought The Cribs would be announced for this year, they did a few gigs in and around Bearded if I remember rightly. They're one of my favourite bands so would love to see them on the line-up for 2025. Wouldn't mind The Coral either.
You'd need to apply to festivals individually. Many/most of them will have information on applying on their websites.
Generally, the recommendation is to start at smaller festivals and work up, rather than jumping straight in at Glastonbury - pitch fees at Glastonbury are very, very expensive and so you want to have a full grasp of the business costs, staffing requirements, demand, and scalability before you even think about committing to that.