Bowler made his first-team debut for Ian Holloway's QPR on the final day last season in a defeat at Norwich and is expected to go into David Unsworth's under-23 squad at Goodison Park.
The youngster has signed a three-year deal.
Bowler signed his first professional contract with QPR in March but has seemingly impressed enough to arouse the interest of bigger clubs.
He is described as a left-footed winger who can play off either flank.
In an interview with the Everton club website, Bowler said: “I’m really excited to join Everton – it’s a fantastic opportunity for me.”
“This is a club on the up at every level. I can’t wait to get started, meet the other lads and begin working with David Unsworth."
“I’m a direct player, I feel like I can bring excitement in the final third and this is the perfect place for me to continue my education and development.”
| Welcome to #EFC, @JoshBowler10!
— Everton (@Everton) 7 de julho de 2017
The 18-year-old has signed a three-year deal and will link up with #EFCU23s: https://t.co/MqqyxsTnwP pic.twitter.com/haqJzjRtg6