There are many possible trees in your crab apple. You will need to decide what you would like from it before making decisions or taking advice.
I cannot see all the movement in the trunk in a couple of 2d pictures. There is so much more to see in real life that decisions could change a lot but I have a couple of rough options for you to consider.
I think my first is what Raging Bull has already put into words. There won't be much left after this pruning but be assured that it will produce new buds and grow back very well.
It will probably be a smaller tree which will be OK if it has smaller fruit but may look a bit odd if this crab variety has large apples. Also remember that smaller bonsai can be harder to keep alive and develop properly. This virt just shows the cuts. Growing branches from what's left and any new buds is up to you but it is just a standard informal upright tree I think.
crab 1 cuts.jpg
If you'd like a slightly larger tree, there's another spot to cut up higher. This time I've also tilted the tree a bit to the left to make it a bit more upright. The larger size should give you more room to grow branches and display flowers and fruit in season. I've even managed to get some new branches and foliage on your new tree

with my rather primitive virt skills
Crab wiggs 2 virt.jpg
I also think there is a possible semicascade or maybe even a cascade in there if you wanted to go that far.
You do not have the required permissions to view the files attached to this post.