Question

wing things in the letter you write,
Address (sender's complete address)
Date (date/month/year)
Salutation (greetings to the person you are writing to)
Body
Introduction
Main content
Conclusion + End of letter
Closing (way of ending the letter)
Name or signature​

Answer 1

Answer:

Yes this is the correct format for informal letter so where is your question?

In letter you will write all of those because it is the format

Answer 2

Answer:

SEMI-FORMAL TO INFORMAL REGISTER FOR INFORMAL LETTERS - DEFINITION

A semi-formal is a letter to a known person. However, the formality of the language really depends on the relationship you have with this person. For example, if you're writing to your uncle or neighbour then you need to use a respectful tone.

Opening Salutation: Dear Mrs. Smith, Dear Mr. Jefferson,

Complimentary Close: Yours sincerely, Warm Regards, Kind Regards,

On the other hand, informal letters contain informal language, almost like a spoken language. Nonetheless, writing has its own conventions and you need to follow them. The language is very informal and colloquial. In this letter, idioms are also permitted with abbreviated forms such as I'm, He's, etc.

Opening Salutation: Dear + name of the person, Dear Charles,

Complimentary Close: Best Wishes, With love, Best Regards,

So, always use a proper style of letter depending on the person you're writing to and his/her position.