How to write a covering letter for visa application?

I’m going to visit Malaysia for 10-12 days just for a tourist purpose. Attaching a covering letter with visa docs is a mandatory requirement. I’m trying to find out some samples online but to no avail.

I need to address to the Malaysian consulate for the purpose of my visit. I don’t know what info should I write and how long? What correct format should I follow ?

Dear Sir/madam?

Subject: ?


Will this sample work?