OK, apologies for being a bearer of bad news. **Bearing in mind that as mentioned, the 'ringbone' might not actually cause her much grief for a fair while at least, also with only a few pics & little info to go on, maybe not quite as it seems... So, first 'port of call' I would absolutely, as Jaydee suggested, have a good equine vet come check her out & xray, to see for sure what the extent of the damage is. How old is the horse & what is her history?
Also get the horse well trimmed, to get her feet in better shape - I'd do all that before I'd consider doing any jumping or such with her. I'd actually only ride/work the horse lightly & on yielding footing until her feet are in much better shape.
Now, first the foot question. As said in your other thread, rings & ridges like that are commonly diet/metabolic related, but can be from other causes too, including mechanical. As they are relatively uniform on all feet, pretty frequent, I would be thinking it's systemic. But there are also some pretty significant mechanical issues as well, which will be able to be corrected with good hoofcare & management.
I've drawn on your pics to emphasise the 'ledges' above the coronary borders on all feet, and also that the rear of the hoof walls, in fores at least, are up high on the lateral cartilages - there's little 'foot' above the walls at the heels! Which indicate the hoof walls are pushed up around the internal structures, or, alternately, you can think of it as the foot/bones have 'sunk' or dropped low within the capsule. This is unfortunately common, from horses being left peripherally loaded, be that bare or rim shod, particularly if on hard footing - that means, hoof walls are taking the brunt of the horse's load, with little or no support underneath the foot. Trimming to load the soles & frogs more(tho that may mean she needs padded boots or such even on yielding footing for a time, esp if they're really weak/thin) and keeping walls level with the sole & frequently enough trimmed so they don't overgrow will relieve them & allow them to start to 'relax down'.
I've also drawn on, to emphasise the long & 'run forward' heels of the fore feet. Can't tell from these angles whether/how much the toes may also be run forward, but I'm guessing they are, despite being relatively straight. I've also emphasised the significant quarter flares on the right hind, and flare to the medial side of left fore. All that can also be corrected with good farriery.
Now for the legs... second pic is where I've emphasised lumps & bumps - aside from blatantly obvious ones on right hind fetlock. If they're hard lumps, they're osteo arthritis - calcification - and on the fetlock this is called 'ringbone'. You can do some reading about ringbone & here is one web page for starters; https://barehoofcare.com/index.php/h...rehab/ringbone
There are some lumpies above the fetlocks too - tho I'm guessing it's an old fence injury on the right hind cannon. The left knee especially looks funny, but as mentioned earlier, could be just from the high/weak heels causing her to be 'over at the knee', so good farriery could correct that too.