Sodium Chloride is ordinary table salt
You have a small sodium atom with a positive charge Na+, and a larger chlorine atom with a negative charge, making it a Chloride ion, Cl-.
This ion formation has resulted from Na transferring one of its electrons to Cl. there opposite charges then attract them to each-other.
Because the electrons are transferred rather than shared, we know that the bond is Ionic, rather than covalent.
Most ionic compounds, if not all, are salts that form a crystal lattice structure, due to the opposite charges in the molecule.
Think of it like this
Na+—Cl-
Cl—-Na+
Na+—Cl-
That’s how the molecules attract and stick to each other. That would continue until you ran out of NaCl molecules.