The negotiations had been going on for a while this summer, as Swansea rejected a bit of £40m before the deal was eventually agreed.
When the deal was confirmed it made Sigurdsson Everton's record signing, £20m more than the previous record paid for Michael Keane earlier in the window.
Sigurdsson said: "Personally, it is not up to me how much the club has paid for me or how much was paid. I put the pressure on myself to play well for the team, create and score goals for the club. That's all I need and that's the only thing I focus on."
The Toffees have spent over £100m on eight signings this summer as well as obtaining Cuco Martina and Wayne Rooney on free transfers and Sigurdsson said it's this ambition which attracted him to move to Goodison Park.
He added: "The club is highly ambitious and you can see that over the last couple of years. They have been making the squad bigger and stronger with a very good manager.
"We want to continue the good progress the club has been making over the last couple of years and try to improve over the next few years.
"It has always been a tough club to play against, I am looking forward to not having to play Everton this season. It's a club on the rise and I want to be part of that."