The Merseysiders announced on Monday they had agreed an £8.6million deal with the Dutch outfit for the midfielder.
Moyes said: "He's a really good player, but he's not signed yet, he's only part way through his medical, so there's a bit to go before we can confirm anything.
"He's someone who we've liked for a long time. He's young and he's certainly an up-and-coming prospect, which we like the sound of. He is somebody who we think can help us."
If everything goes smoothly, the 23 year old could make his debut against Aston Villa on Saturday.
Fer told Voetbal International: "A transfer in January is not ideal. But I think Everton is a nice club and a serious challenger for a place in the Champions League.
"The Premier League is a league that I've always wanted to play football in. With my style of play, I think England will be the right place to go."