Blundell has been slowly building minutes at United following her return after giving birth in March, making three appearances for the Reds so far this term.
Now set to gain vital opportunities on Merseyside, the 31-year-old is linking up with the Toffees, working under manager Brian Sorensen.
Hannah joined the club from Chelsea in 2021 and has in total made 84 appearances for United.
This will be her first loan spell away from the club, something both the Reds and Everton can benefit from.
The Toffees are currently 10th in the WSL, most recently recording a huge 1-0 win over Chelsea in December.