The closing of your cover letter includes a valediction (sincerely, regards, best regards, your truly, etc.), your written signature, and your name and title.
It's important to always include your actual signature and not a computer-generated signature to personalize the letter. Your signature should go in between the valediction and your name, so you'll want to leave a few extra spaces there.
At the end of your cover letter, after your title, including the word "Enclosure" signifies to the recipient that the cover letter references additional documents.
View the full-size version of the cover letter example shown here.