Final answer:
The letter writer's initials are followed by a colon or slash and the typist's initials are called the identification line, and it is placed below the signature block in a formal letter.
Step-by-step explanation:
The combination of the letter writer's initials followed by a colon or slash and the typist's initials is known as the identification line. This identification line is typically placed below the signature block, which includes the closing, the handwritten signature, and the writer's typed name. In the context of a formal letter, the sender's address is listed first, followed by the date and recipient's address. After the salutation, comes the body of the letter, the closing, and then the signature block. If there are any additional materials included with the letter, such as a resume, they are noted as enclosures below the signature block.