The 20-year-old was at Goodison Park on Saturday to see Everton’s season-opening Premier League loss to Chelsea by a 1-0.
Onana was also a target for West Ham, who had set a price for the player.
He told evertontv, “It feels amazing to join Everton.” “I know it is a huge club—among the biggest in England. I want to be a part of it for a very long time.”
After James Tarkowski, Dwight McNeil, and the loanees Ruben Vinagre and Conor Coady, Onana is Everton’s sixth summer acquisition.
Onana, who made his international debut for Belgium in a June match against the Netherlands, credited Everton manager Frank Lampard for influencing his choice to leave.
He stated that everyone in this room demonstrated that they really desired me and had a plan for me.
“The conversations I had with the manager and football director were precious (Kevin Thelwell). I relished their instructions on how I should play.
“The manager was a midfielder who competed at the top level and earned several awards. To have his attention means a lot to me, and I believe he has a lot to teach me.
“They both have a lot of ambition, and I’m the kind of man that values ambition, so it fits,” he said.
Lampard declared: “We were eager to get Amadou to a contract with Everton.
“He has many excellent traits that will bolster our midfield; at just 20 years old, he still has a tonne of room for improvement.
We’re all eager to see what he can add to the team after I explained why Everton was his best club.