Hangul syllable Heoss

On its own, 헜 spells a syllable, not a complete word.

It combines initial ㅎ, vowel ㅓ, and final ㅆ. Hangul arranges its letters in square blocks, each representing one syllable; the Korean word around this block supplies the meaning.

Hangul was created in 1443 and publicly introduced in 1446 as a sound-based way to write Korean that ordinary people could learn. Those dates describe the script, not this individual syllable.

why does 헜 sound like 헛?

At a word edge, both finals can sound like a closed t.

헜 is written with final ㅆ; 헛 has final ㅅ. Korean pronounces several different final consonants alike at a word edge or before another consonant.

That sound overlap explains why the syllables can be confused by ear, but it does not make the spellings interchangeable.

how do i type 헜?

Enter ㅎ, ㅓ, then ㅆ with a Korean keyboard.

A Korean input method combines the three jamo into one syllable block. Unicode can also represent the syllable as separate jamo; NFC normalization, Unicode's composed form, recombines them.

Hangul fonts can place the same components differently inside the square cell, especially the final consonant. A changed silhouette is a typeface difference, not a different character.