What Cha is
Cha (چ) 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 and Kurdish.
Arabic has no ch. The sound is carried by ج in Arabic borrowings, and Persian formed چ by giving ج three dots.
How Ilm ul Huroof reads Cha
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 Cha, that base is Jeem (ج), and a name written with Cha is read through Jeem's qualities and abjad value.
Anyone offering you a separate classical reading for Cha is inventing it. We would rather tell you where the tradition stops.
Cha in names
Names carrying Cha are usually Persian, Turkic, Urdu or Pashto in origin rather than Arabic. On their AsrNaam pages the letter grid shows Cha as written and reads it through Jeem.
Browse all letters, read the introduction to Ilm ul Huroof, or see why a name's Urdu spelling matters.
Cha 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.
Cha 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 Cha keep their al- intact when they carry one.