Question

what is the format of informal letter​

Answer 1

Explanation:

Informal Letter Format - Greeting

Now since you know the person you are writing to, the greeting can be informal as well. If it is a friend or someone close to your age you can greet them by their first name, like “Dear Alex”.

If you are writing to your relative like your mother/father/aunt/uncle etc, you may greet them as such, for example, “Dear Mom”. And if you are writing to an elder person, someone you respect greatly you can address them as Mr or Mrs. Like say for example you were writing a congratulatory letter to your teacher, it can be addressed as “Dear Mrs. Alex”.