The package provides hyphenable spacing out (letterspacing),
underlining, striking out, etc., using the TeX hyphenation
algorithm to find the proper hyphens automatically. It also
provides a mechanism that can be used to implement similar
tasks, that have to treat text syllable by syllable. This is
shown in two examples. This version is a merge of the original
soul package from Melchior Franz and the soulutf8 package from
Heiko Oberdiek and supports also UTF8.

Homepage:
https://ctan.org/pkg/soul
