What does the last paragraph of business letter describe?

The last paragraph of a business letter is known as 'the call to action' paragraph. In other Words, state what you want the recipient to do in response to your letter. It is surprising how often someone writes a letter without telling the recipient this, leaving the recipient to guess what you expect them to do, or at the recipients discretion, to do nothing. You may think that the information provided in the body of the letter will tell them what you want them to do, but it may not be as obvious as you think, especially if you are writing to complain about something.

The last paragraph should also include the senders contact info (address, email address, phone number, etc.), and any dates that are essential.

The last line of the last paragraph should thank the recipient for their time and/or their effort. Even if the letter is sent just to inform the recipient of something and no action on their part is required, thank them for their time and attention.