What is pe coated fabric?

It's fabric coated with a polythene film. The sort of thing from which waterproof tablecloths are made.

Coatings vary, as does the fabric. PVC (poly vinyl chloride) is falling out of favour gradually, as it's not very environmentally friendly, but PE (polyethylene aka polythene) and PEVA (a copolymer of polyethylene and EVA (ethylene vinyl acetate) are readily available.