Example
Before
Read this first
After
R̲e̲a̲d̲ ̲t̲h̲i̲s̲ ̲f̲i̲r̲s̲t̲
How it works
A combining underline character (U+0332, or U+0333 for double) is added after each letter. Some fonts and apps join them into a continuous line, others show short separate dashes under each letter.
Things to know
Screen readers may read these characters oddly or skip them, and search engines don’t treat them as ordinary words. Use them for a word or two of emphasis, not for whole posts, usernames you want people to search for, or anything that needs to be accessible.