What is a reference line in business letter?

A reference line in a business letter is an optional line placed at the end of the letter, before the sender's signature, that provides additional information about the letter or its contents. It is typically used to include a file number, reference number, or other identifying information that may be relevant to the recipient.

The purpose of a reference line is to make it easy for the recipient to quickly find the letter in their records or to cross-reference it with other correspondence. It can also help to ensure that the letter is properly routed within the recipient's organization.

The format of a reference line can vary depending on the company or organization, but it typically includes the following information:

* The word "Ref" or "Reference"

* A colon (:)

* The reference number or other identifying information

For example:

```

Ref: 1234567890

```

```

Reference: Customer Account Number 1234567890

```

It is important to note that a reference line is not required in a business letter, but it can be a useful tool for organizing and tracking correspondence.