Closing your Query Letter is the easiest part of your initial correspondence with a literary agent.
After you’ve written your greeting/introduction and hooked the literary agent with the premise and plot of your novel, you might want to end your Query Letter with a brief note about yourself.
Did you notice the word “might?” You do not have to write anything about yourself. Only include biographical information if your experience is relevant to your book. Are you published already? Has your writing won any awards? Do you have a degree in creative writing? Are you a police officer who has written a crime drama? If there’s really nothing—don’t worry about it. Your story should speak for itself—it is the hook—not you (unless you are famous, I suppose). You don’t have to include any “bio” information because it probably won’t matter at this point. I’m not trying to be insulting here—remember that the goal of the query is to get the agent to request your story. If having biographical info will help with that, put it in. If the bio doesn’t pertain to the story, skip it.
Lastly, sign off by thanking the agent for her time and say that you can send the completed manuscript at her request. Make sure your contact info is on the letter/in the email somewhere.