Do I have to use any sealers for peel and stick tile after I use a seam filler on the joints and screws... thanks

What are you actually laying the lick and stick tile on?

I use the term lick and stick simply because I've seen to many square peel and stick tiles fail and if anything they usually shrink in time and gap. The other reason I don't like square tiles is because any water that's spilled on the floor is trouble later. I use a ton of peel and stick tile in rentals simple because its quick and cheap to put down and replace. But the best vinyl is sheet goods that covers the whole floor.

Peel and stick are a marginal product but can work if you prime the floor before installation. Never try to install directly on a cement floor.