Is Morse Code Capitalized?

Write it as "Morse code": capital M, lowercase c. "Morse" is a proper noun from Samuel F. B. Morse's name, and "code" is an ordinary word that stays lowercase mid-sentence.

She learned Morse code in the Navy.

Why "Morse" gets a capital

The code is named after Samuel Morse, who built the electromagnetic telegraph and sent its first long-distance message in 1844. The Library of Congress keeps his papers on the invention of the telegraph. Names stay capitalized even when they become part of a common term, the same as Braille or Celsius. The history page has the full story.

When "code" gets a capital

Only when something else calls for it:

Situation	Example
Start of a sentence	Morse code is still used on ham radio.
Title case headline	How to Learn Morse Code
Formal name of the standard	International Morse Code
Middle of a sentence	I'm learning Morse code.

"morse code" in all lowercase is common online, but standard style keeps the capital M.

Morse code itself has no capitals

This is the other half of the question. Morse has no upper or lower case. The letter A is .- whether you mean "A" or "a."

Decoded Morse is traditionally written in capitals, which is why our translator shows its output in uppercase. If case matters in your message, you have to spell it out in words. You can see every letter's single pattern on the alphabet page.