Lewis Structures of Ammonium Ion (RED) and Chloride Ions (BLUE) are attached below.
Lewis structures are those structures which shows the environment of electrons in a molecule. These structures basically depicts the bonding electrons and non-bonding electrons also known as Lone pair electrons.
In attached structure it can be seen that the ammonium ion is made when nitrogen atom is forming four single bonds with four hydrogen atoms and the formal charge on nitrogen becomes +1. While, in case of chloride ion the chlorine atom has four lone pair of electrons and has a formal charge of -1.