Letters are of two types; formal and informal. Formal letters include letters to the organizations and institutes while informal letters are the ones written to friends, parents, and relatives.
Letter layouts are very important. I highly suggest you go through layouts (commas, breaks, etc) to get easy marks.
Letters can be broadly categorized as follow:
- Letter to your father (tell about your studies, asking him for a fee, etc)
- Writing to a friend (lending, thanking, or wishing him/her)
- Letter to close relatives like a sister, brother, etc