Does these two orchids have crown rot, if so, could anyone suggest how to treat it. I already sprayed the crown of the second orchid with 3% peroxide and dried it with paper towel but it didn't seem to help, so if anyone have any advice it would be more than helpful.

I do NOT think it is crown rot. You could sprinkle cinnnamon into the center of the crown since it might help.
I don't see anything wrong in the first 2 images.
Welcome to the Orchid Forums. We have numerous threads here regarding Phalaenopsis orchid care. There is a great 'sticky' on starting with Supermarket Orchids-Phalaenopsis. Those items will give you all kinds of great information. Such as watering, fertilizing, light and repotting. They should be repotted every two years, once a year would be better.

Thank you for your answer. So you think cinnamon will help with my other orchid (last two pictures). Also another question. Does anyone knows what could cause orchid leaves to split , it's a common thing happening with my orchids.

Yes cinnamon can help.
Leaves split lengthwise? Perhaps heat stress. How warm is it where they grow?

Yes lengthwise in the middle, but sometimes on the tips of the leaves as well. It's between 28-38°C/82-100°F and the humidity is usually pretty high 60-75%.
Here are some examples:

Boy Klara, your orchids look nice and healthy! Nice growing!
It is very unusual for a Phalaenopsis leaf to split across the leaf. Are you sure no one is doing it as the plant gets picked up? Do you have a kitty cat who might walk around the plants? I don't think that leaves normally just split like that.
But if they stay green and look healthy, I would not worry. Like I said, they look nice and healthy!!!

Well two of the leaves were slightly damaged (cut) on the edges of the leaves when I bought them, and I heard somewhere that leaves could split as a sign of dehydration which they were a little bit when I got them but nothing dramatic, overall healthy. But otherwise no cats or other animals that could harm them. The only thing that I'm noticing is that more and more orchids get dried up "middle line" so it concerns me a little bit that more leaves would split in half lengthwise. Could it be that I'm under watering them slightly. I usually water them once around 80% of the roots get that silver tint.

Thanks in advance

Klara, that silver tint is called velamin. Older roots lose that color somewhat. When you water them thoroughly, that gray should all turn green. The roots actually have chlorophyll in them which provides the green color.
If your splitting is coming from dehydration then watering more and deeper into the pots might help.
But in a sales area, either in Home Depot or in an orchid business, those plants constantly get shuffled and moved around. Leaf tips get bumped and bruised and even damaged. Sellers will trim those ends.

I didn't know that older roots don't get silver tint when dry, this time I'll be watering them more carefully without waiting for all the roots to become silver. Every time I water them I leave them sitting in a pot full of water for 10 minutes to make sure the roots have enough time to soak up the water and as you said become bright green. Thank you once again!

No problem