There is no easy way to communicate tone while texting. Younger people have invented a solution, using capitalisation. To younger people,

this sounds like a casual conversation at a quieter volume.

This sounds like a slightly louder, more authoritative tone of voice, as if you were orating to an audience or group of people.

AND THIS SOUNDS LIKE YOU'RE YELLING OR SCREAMING.

Tone differentiation is a relatively new invention. Many older people don't see all-caps as screaming or yelling, it's just not how they communicate.

But young people do use these context clues in texting to communicate mood, which is a vital element of language. Just because you in specific don't communicate in this way doesn't mean that this form of communication is "wrong" or "incorrect"—the most correct way to write is the form that communicates your meaning, your intention, your mood, and your tone best.