The Lewis dot structure for HCl has hydrogen's symbol, H, on the left side, chlorine's symbol, Cl, on the right side, two dots between the two and an additional six dots around Cl.
Hydrogen has a single valence electron, while chlorine has seven valence electrons. In order for the two elements to bond, they need to contribute one electron each to form a single bond. The Lewis dot structure for this shows the two shared electrons between H and Cl as two dots. The other six valence electrons for Cl are arranged as two dots on top, two below and another two dots on the right side of Cl.