William Shaksper of Stratford upon Avon left behind six signatures. Apparently, but not certainly, all are his. This is the extent of his known writings:
(See below for more information about the Shaksper signatures.)
The true Shakespeare, Edward, Earl of Oxford, left behind a few different forms of signature. He used a “crown” signature from November 1569 until the funeral of Queen Elizabeth on April 28, 1603, when the Tudor dynasty ended.
Hank Whittemore's Shakespeare Blog 