I hope my letter finds you in the pink of your health. How are the kids doing? It’s been so long since we spoke, so I thought of writing to you today. (This is the introductory paragraph and must present your greetings and you should ask about the recipient’s well-being).
I wanted you to know that I have got a new job and I am coming for a conference to your town next month. I hope you will be at home so that we can catch up. (This is the body of the letter and must contain your main reason for writing the letter. This is the most descriptive part of the letter and you can elaborate on the details here).
Third paragraph: Hope to see you soon and give my love to your children. (The last para must round off the letter and one bids goodbye in this part).