dabac

Strictly speaking you need a fork that has:
- the same steerer tube diameter
(Smaller steerer in bigger head tube is doable, but let's not go there)
- the same steerer tube length - or longer - than what's already on there. If threadless, and you want the bar higher, you must search for a longer steerer than what's on THE BIKE. The spec sheet value isn't important. If you have a threaded headset, fork needs to have threads enough to do up the headset.
- the right dropouts if you want to keep using the wheel. In this case a 9 mm q/r axle.
- it needs to be able o use the right kind of brake system.
- if rim brakes, it needs to be made for the right wheel size
- AND to keep the bike handling as it should, and avoid overstressing fork and frame you need to stick as close as possible to the axle-to-crown measurement of the old fork.
This will obviously be impossible since your express wish is to increase travel. Which will mean that while still rideable, the bike will handle differently.
There's rake that should be matched too. But no point if you're going to a longer fork.
The really big thing to consider is this:
A bike only fitted for 35 mm travel is obviously not meant for rough riding. If you want to fit a longer travel fork you probably WANT to ride it harder. There are NO guarantees that the rest f the bike will survive that.