Application Letter With Referral. The person providing a reference is called a referee. A letter of referral, also called a letter of recommendation, is a document you may need to provide when applying to a job, internship, school or volunteering Typically, people ask someone they have a positive experience with to write their letter of referral.

Reference letters are used in a wide variety of situations; there is no definitive list that covers all possible scenarios.
If you are applying through a referral in the United States, then a To add my small piece from a UK perspective, it's very important to check on a firm by firm bases on the need to submit a cover letter with your application.
That gets the job done, and it's short. If you referred by someone else this will take employers attention and they would give closer look to your application letter and CV. By sending a referral, you are putting both your reputation and that of the company you're referring on the line, so be sure you are completely confident in its ability to provide top-notch service.