You'll need a fork that is 26" with a QR dropout, and a disk brake caliper mount on the left.
Any replacement fork will need to fit through your head tube, which looks to be a 1" straight, and uses a threadless stem. Avoid anything that needs a quill stem or has threads visible at the top of the steerer on the outside. Also, the steerer needs to be long enough to go through the head tube and have at least 60-70mm out the top.
Your bike appears to be a low-spec Halfords house brand. I would keep that in mind before dropping a lot of cash on new parts. Also, reviews suggest that it was never a great bike with phases like
Creditably detailed chassis, but a deafening, self-destructing disaster off-road.
I would suggest finding a suitable used fork, even if it comes from a donor bike.
Another option is to disassemble and service your current fork.