The Argentine joins Everton on-loan to the end of the season with an option to buy.
The 22-year-old has past Premier League experience with Southampton.
Alcaraz told evertontv: “I am very happy to join Everton, such a great club, with a very good fanbase. I'm very happy and I'm looking forward to start training with my teammates and see the fans at the stadium.
“I am ready for any challenge with this beautiful club so that's why I came and accepted the offer to keep fighting for my dreams. I want to tell the fans that whenever I wear this shirt, I will give my best, I will give everything I have to take Everton to the top, which is where they deserve to be.”
On his new signing, Everton boss Moyes said: “We’re happy Carlos has agreed to join us on loan until the end of the season.
“We’ve been looking to add players to the squad to give us more depth, particularly after the recent injuries we’ve picked up.
“Carlos has Premier League experience, he’s still young and we believe he can bring some energy to the team which will help us between now and the end of the season.”
Everton Director of Football, Kevin Thelwell, added: “Charly is a welcome addition to the squad and a player who brings Premier League and international experience and, at the age of 22, has potential to get even better.
“He is an excellent ball carrier who can add real quality to our attack, and we think he is a player who will really excite Evertonians.”