Here's why:

* Electronegativity: Oxygen (O) has an electronegativity of 3.44, while fluorine (F) has an electronegativity of 3.98. The difference in electronegativity between the two elements is relatively small (0.54).

* Sharing of Electrons: In a covalent bond, atoms share electrons to achieve a stable electron configuration. Since the electronegativity difference isn't large enough for one atom to completely steal an electron from the other, they share the electrons, forming a covalent bond.

Important Note: The bond between oxygen and fluorine is a polar covalent bond due to the slight electronegativity difference. This means the shared electrons are slightly closer to the fluorine atom, creating a partial negative charge on the fluorine and a partial positive charge on the oxygen.