26 letters in French. The basis for spelling your name.
French letter names are mostly different from English. Two patterns to remember: letters that end with "-ee" in English (B, C, D, E, G, P, T, V, Z) end with "-ay" in French — so English "ay/bee/see/dee" become French "ah/bay/say/day". A consequence: French J sounds like English "jay" but actually means J… and French G sounds like English "zhay" but means G — easy to mix up.
U sounds exactly like the Chinese word for fish (魚) — purse your lips for "oo" but say "ee".
Spelling out names also uses connector words: deux for any doubled letter (e.g. "deux R" = "RR") — except W, which is its own word "double-vé". Espace = space between words; tiret = hyphen. For email addresses you'll need arobase = @ and point = "." (dot).
You'll hear each letter spoken once, anchored with a French name (e.g. "B comme Bertrand"). Pick the matching letter from four choices.