PA film, in plastic packaging industry, usually mean biaxially oriented Polyamide film (short as BOPA), as biaxially oriented process will enable the molecular align in an more order state, that will enable the final PA film with better mechanical strength, heat resistance, transparency, etc, a better substrate film for packaging purpose.
Nylon film (short as NY), is the most popular nickname for PA film, so when you ever come to NY or PA in flexible packaging, just make them the same thing (even different brands in some cases).
PA film is widely used in plastic packaging as of superior property that other films are not able to provide
Barrier to oxygen
Great Mechanical Strength