Expert Alison Doyle made a sample sick leave letter that can be found in the Career section of About.com, as of October 2014. The letter provides an example of the format and information to include in a medical leave letter. A sick leave letter, according to this site, needs proper contact information and a formal request that contains the illness details, as well as openness about providing more details later.
Another example of a medical leave letter is one posted by Steve Jobs in 2009 following the discovery of his medical problems. In it, he wrote about his illness without going too far into specifics, instead focusing
on his actions in response to the sickness and the length of his leave. This is a sick leave letter from the other perspective, where the employer is informing the employees of a leave of absence.
About.com offers many other sample letters for job-related concerns, such as recommendation, thank you and resignation letters. These letters serve the purpose of providing pleasantries to a colleague and informing another colleague about something important.
According to an article published on Forbes, a resume-related letter called the cover letter should not be stiff and should contain some informal tools like jokes. Other letters are similar in that each letter requires tailoring to the person for whom it is written. A cover letter requires the writer to think of common contacts and consider what the employer needs.