Step-by-step explanation:
The bond between two oxygen atoms is covalent (covalent bonding is bonding between Non metals (the electrons are shared)).
The bond between the Na and Cl (NaCl) is ionic (ionic bonding is bonding between a metal (in this case the Na) and a non metal (the Cl). This type of bonds deals with the metal losing electrons and the non metal gaining electrons. The metal therefore become positively charged (so it becomes ionic) and the non metals gain electrons and become negatively charged (also becomes ionic/ forms an ion). The opposite charges attract each other and this is why they bond.