The number 34 shirt will be worn by Anwar El Ghazi, who scored 10 goals in the premier league last season.
The player from Villa will be on loan to the Toffees until the end of the season.
He becomes the third signing of the January transfer window, following the arrivals of Vitaliy Mykolenko and Nathan Patterson.
The sale of Lucas Digne to Villa was worth up to £25m.
El Ghazi said he couldn't wait to start atEverton.
I want to get into the team, fight for my place, and help the team get where it belongs - that is much higher up the table.
I can score a goal at any time. I can add value with my pace and technique. I am good in one-on-ones. I can't wait.
El Ghazi scored 10 goals in 17 starts and 11 substitute appearances for Villa last season.
He scored the opening goal in Villa's Championship play-off final win over Derby, helping them return to the top flight.