Ahydrogen atom has one electron. how many covalent bonds can hydrogen form?

The goal of any atom really is to have an outer shell with the same number of electrons as its corresponding row's noble gas. Hydrogen's closest noble gas is helium, which has two electrons. A covalent bond is the sharing of two electrons between two atoms, so hydrogen would only need to make one covalent bond to fill its shell. Hence, hydrogen makes one covalent bond.