Its been my experience that most (ie: not all) power steering reservoirs have a non-serviceable screen at the bottom. One-way, meaning on the supply side to the pump. The return line usually feeds fluid back into the reservoir above this filter.
Ford's part number for a new reservoir is 5L3Z3A697AA.
On Rock Auto, for example, Cardone makes a replacement - $20.
https://www.rockauto.com/en/catalog...411108,steering,power+steering+reservoir,7378
About every year or two I use a turkey baster to empty the reservoir as much as I can, add fresh power steering fluid, drive around a few minutes with lock to lock turns, repeat 3-4 times until I've used up the new quart of PS fluid. I use Prestone brand fluid, which is clear. As it ages/gets dirty it turns yellowish. With transmission fluid, in my experience, its always nice and red - giving no indication its time to replace.
One *could* remove their reservoir and try backflushing the supply side to clear a clogged filter, but thats just messy and a replacement is too inexpensive. Not only that, no reason to run the risk of the filter tearing.