Writing letters is not very easy. There are various formats and ways of formulating a letter. Not following the correct form of words or structure can make the letter look ugly or indisciplined, costing the person writing it some serious purpose.
When we say letters, one of the main features is the corresponding closings. This is where phrases like yours faithfully or yours sincerely come into being. These are the closing points used at the end of a letter in order to introduce the person who is writing the letter. This is a part of the basic format and a must in almost every type of letter.
However, people are often confused when to use yours faithfully and yours sincerely. There is not much difference, but there can be one specific point under which the two can differ. That is;
Yours faithfully is basically used when the person is writing to someone unknown. They have never met or known each other, and the writer addresses the person as dear sir/dear madam.
On the other hand, yours sincerely is used in a letter when the person is writing to someone known. They have spoken before, and the writer addresses the person as Dear Miss/Mr/Mrs.
Also, Yours faithfully is usually used in formal business or job letters. On the other hand, yours sincerely is commonly used in letters that are a little informal and friendly in nature.