For the most popular and academically idolized playwright in history, we know very little about the life of Shakespeare. The details of his upbringing and education are hazy, and as for his later life, we are often reduced to sifting through the text of his plays for references which might give us some clues. We know he was born in Stratford-upon Avon, on the 23rd of April, 1564. We know that he had one brother and one sister, married a woman named Anne Hathaway in 1582, and died on his birthday in 1616; the rest is all down to speculation.
The main reason we know so little about such a great man is simply that he was alive in a time when people just didn't write things down. Records that were kept were lost or stolen, destroyed by damp or by the fires which plagued London at the time; add to that the tiny chance of a poorly-kept paper document surviving until the present day, and it's no wonder we know barely anything about the man. His plays themselves only survived because a friend of Shakespeare's had them published out of his own pocket (and even then, some were overlooked and are now lost forever).
The few records which we do have are official ones, certifying his baptism, marriage, and last will and testament.
A few instances of his signature exist, all of them using a different spelling of his name, but interestingly none of them the one we use today. A lot has been read into that, in fact some self-proclaimed experts have even claimed this as proof that the man was illiterate and that the plays were written by someone else. This seems a bit extreme to most scholars, and many of them claim instead that this is simply a product of the lack of structure in language at the time. Since English was mostly just spoken in the sixteenth and seventeenth century (only public records, legal documents and literature ever really needed to be committed to paper), you could spell your name any way you liked as long as it was verbally recognizable. William Shakespeare most likely saw no problem with jotting down his name in a vaguely phonetic way on each of the rare occasions he needed to sign it.
Beyond these concrete records, scholars are forced to simply guess almost blindly, and all we have is speculation about the life of William Shakespeare. We think he probably went to a local school, we think he most likely didn't go to university, we assume he was a schoolteacher for a time, or possibly a lawyer, or he worked for a troupe of travelling players for a short time... All of this based simply on knowledge that he displays in his plays, and the opportunities which would have been open to him at the time. In short, we just don't have much of a clue.
So we have the facts, the kind that councils and officials are interested in, but we know virtually nothing about the life of Shakespeare the man. His personality, attitudes and quirks were never recorded, or if they were they are now lost. All we have are a handful of brief documents, a few shoddy signatures, and a collection of plays which have mesmerized the whole of Western culture for centuries.