Capital sentence in mail is used for shouting

I think there may be a bit of confusion here!

In the English language, "capital" has a different meaning when used in the context of writing.

In writing, "capital" refers to the uppercase letters of the alphabet, such as "A", "B", "C", etc. These letters are used to start sentences, proper nouns, and titles.

When you write a sentence in all capital letters, it's called "capitalizing" the sentence. This is often used to emphasize the importance of the sentence, to indicate that it's a title or heading, or to add emphasis to certain words.

For example:

• "I AM GOING TO THE STORE" (capitalized sentence)
• "I am going to the store" (lowercase sentence)

So, to summarize: "capital" in the context of writing refers to uppercase letters, not shouting or loudness.