Please help!

I have 2 cats, both female. One cat got to the point that she stayed in heat and during those times she would pee on any shoes she could find. We recently got them both fixed. But the same cat will still only urinate on shoes, its ruining my floors and all of our shoes. Also after being fixed I have piles of feces in my bathroom floor every morning before I go to work and every day when I get home from the same cat. It's just one of them acting this way

How many litter boxes do you have?  How often do you clean them?  Have you cleaned areas where she's gone to the bathroom inappropriately with an enzyme cleaner?

1 litter box, scoop it out daily. Empty and completely clean at least once a week. She doesn't have particular areas she goes to, just where ever a shoe is at that she likes and she will use that shoe or shoes all day. This used to just be when she was in heat, shoes, boxes(even like our food boxes like granola bar boxes anything left on counter) and bags like Walmart bags. Got her spayed almost 2 mths ago and now just this week she is back to only urinating on shoes.

Try adding another litter box or two.  She might feel too crowded.  In addition, stop leaving your shoes on the ground.  Clean with an enzyme cleaner anywhere that she has gone.

It's also possible that she has a uti.  A vet should always be your first stop with any abnormal behavior.