A hydrogen atom having 1 electron, why does a hydrogen atom only form one bond?

The H atom has only one energy level (containing 1 orbital, but that is not important). Unlike other atoms with 2 or more energy levels and requiring 8 e- in the outer level to become stable, H only needs 1 one more e- to become stable (like Helium) needing only 1 more e-, it forms only 1 bond, because a single bond is the sharing of 2 e-. Hydrogen shares its electron and the electron from the other atom, thus creating one bond.

H has 1 electron for its stable configuration it requires 1 electron so it shares 1 electron with another element & form one bond

Inner shell of an atom has a capacity of 2 electrons.

1 electron is half a shared pair.

The innermost orbital is full with two electrons, so it only needs 1 more.