Two hydrogen atoms form a molecule by sharing their electrons through a covalent bond. Here's how it works:

* Each hydrogen atom has one proton and one electron.

* Both atoms are seeking a stable electron configuration. They want two electrons in their outermost shell.

* They achieve this by sharing their single electrons. This creates a shared pair of electrons that orbits both nuclei.

* The shared electrons are attracted to both nuclei, creating a strong bond. This bond holds the two hydrogen atoms together as a molecule (H2).

This shared electron pair is what forms the covalent bond, and it's the reason why hydrogen exists as a diatomic molecule (H2) in its natural state.