Use a deck stain
If you would like it solid, like a paint, use a solid stain
Your local Paint Store will have the best products
I can personally recommend Ben Moore, Sikkens, Cabots, and Sherwin Williams products
Stain will look beautiful, but easy on the feet? >>I like "Tread Plex" from SW for a smooth walk.
Having built tons of decks, one thing I caution, make sure your deck is ready to accept products (if it's newer). I've seen PT can take months depending on the weather. Might wanna check with the manufacture.
Quick test: Splash a handful of water on the deck, if it penetrates and dries quickly it should be ready.
If it beads up like a car that was just waxed, wait~