The deal for Zouma was also expected after a deal sheet was submitted, but it took until Friday afternoon for confirmation, with the Frenchman becoming Everton's seventh signing of the summer.
The 23-year-old French centre-back temporarily moves to Goodison Park with opportunities limited under new boss Maurizio Sarri.
The Toffees left it late to make an approach to loan the France global but as both sides submitted their paperwork before the 5pm deadline, the deal was allowed to proceed.
"I don't want to talk only about him because the market is the market".
The uncertain future of Yerry Mina remains up in the air but Jose Mourinho has ruled out a move to bring the Barcelona defender to Manchester United.
'It is important that the club want to fight for something, ' Mina told evertontv.
It remains to be seen how many of Everton's new signings will be fit and ready to play in their opening Premier League game at Wolves on Saturday.