Shakespeare was a pseudonym, according to wikipedia.org. Learn here all the details.
In his surviving signatures William Shakespeare did not spell his name as it appears on most Shakespeare title pages.
His surname was spelled inconsistently in both literary and non-literary documents, with the most variation observed in those that were written by hand.
This is taken as evidence that he was not the same person who wrote the works, and that the name was used as a pseudonym for the true author.
Shakespeare’s surname was hyphenated as “Shake-speare” or “Shak-spear” on the title pages of 15 of the 48 individual quarto (or Q) editions of Shakespeare’s plays (16 were published with the author unnamed) and in two of the five editions of poetry, published before the First Folio.