A signature on a document provides proof of identity, assurances that the content of the document has not changed since it was signed, and evidence that the signer was aware of the document. For these reasons, when a letter is signed by someone other than the writer, that fact must be properly noted by the use of a specific format.
Sign the letter or document with the name indicated in the signature block. For example, if the name typed below the space for the signature says "Robert Smith," then write the name "Robert Smith" in the space provided.
Place a forward slash after the signature. A forward slash looks like this: /
Note your initials after the forward slash. For example, if your name is Jane Jones, you will write "jj" in small letters after the forward slash.
The completed signature will look like this: Robert Smith/jj
Another less popular method of signing a letter for someone else is to actually sign your name in the signature block, and then write the word "for" before the person's name for whom you are signing. If Jane Jones were to sign for Robert Smith in this manner, the signature block would look like this: Sincerely, Jane Jones (handwritten) for Robert Smith (the word "for" is handwritten)