What Pa is
Pa (پ) is not one of the twenty-eight letters of the Arabic alphabet. It is one of four letters Persian added to the Arabic script in order to write sounds Arabic does not have, and it spread with the script into Persian, Urdu, Pashto, Kurdish and Ottoman Turkish.
Arabic has no p. Arabic renders foreign p with ب, which is why Persian added پ by giving ب three dots.
How Ilm ul Huroof reads Pa
It does not read it directly, and this is worth stating plainly. The Science of Letters was built on the twenty-eight Arabic letters, each tied to an element, a divine name and a numerical value in the abjad. The four Persian letters postdate that framework and have no classical reading of their own.
What the tradition does is read the Arabic base letter beneath the added dots. For Pa, that base is Ba (ب), and a name written with Pa is read through Ba's qualities and abjad value.
Anyone offering you a separate classical reading for Pa is inventing it. We would rather tell you where the tradition stops.
Pa in names
Names carrying Pa are usually Persian, Turkic, Urdu or Pashto in origin rather than Arabic. On their AsrNaam pages the letter grid shows Pa as written and reads it through Ba.
Browse all letters, read the introduction to Ilm ul Huroof, or see why a name's Urdu spelling matters.
Pa joins on both sides, so it takes all four shapes. In a word it connects to the letter before it and to the letter after it, and the shape you see depends on where in the word it falls.
Pa is a moon letter. When the definite article ال (al-) comes before it, the l is pronounced clearly and stays audible, as in القمر, al-qamar, the moon, which gives this group its name. Names beginning with Pa keep their al- intact when they carry one.