In informal letters, the term 'dear' is used (like for friends, family). So, you should uphold formality and use the word 'respected' when writing a letter to someone respectable, such as sir, madam, principal, or even family elders. ... Then the correct answer is: Respected Sir.

Is it OK to write Dear Sirs?

A traditional choice for a salutation to an entity would be Dear Sirs, but it suggests you're writing to a group of individuals, it's old-fashioned, and it's gender-specific (see 17.10).

How do you write respected in sirs?

It can be formal or informal depending on the writer's relationship with the recipient. The salutations 'Dear Respected Sir/Madam', 'Respected Sir/Madam' and 'Respected Sir' are very common in Indian English.