Where does “H” come from?

H (Latin) comes from Etruscan 𐌇, from Ancient Greek η, from Phoenician 𐤇, from Egyptian ?.

Ancestry of “H”, step by step

Step	Language	Word	Meaning
1	Etruscan	𐌇	—
2	Ancient Greek	η	Lower-case eta, the seventh letter of the ancient Greek alphabet. Its name was ἦτα and it represented a long open-mid front unrounded vowel:. It is often transliterated as either e or i. It is preceded by ζ and followed by θ
3	Phoenician	𐤇	het; heth
4	Egyptian	?	—