Simms, who is cleared to play in the FA Cup at Brighton on Saturday, is a regular at under-23 level for the Toffees with eight goals in 12 games.
"He's a player I've been aware of for a few years," said boss Neil Critchley.
"Ellis has an outstanding goal record at under-18 and under-23 level and I believe he's now ready for this step into senior football.
"I'm delighted that he's chosen to sign for us, given that he had a number of options available. He will add something different at the top end of the pitch."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!