Question

What did the Declaration of Independence do?

Answer 1

Decleared independence from england.

Answer 2

It declared that England's 13 colonies in North America were not colonies of
England any more.  That meant that they didn't have to do what the King of England
said anymore, and they didn't need his permission to do anything they wanted to do,
and they didn't have to pay taxes to England any more, and England could not take
their crops or natural resources any more, and England should just go away and
leave them alone.

England did not just say OK have it your way.  They sent their army over here, to
spank the colonies and make them behave and keep doing what England said. 
But somehow the colonies won that war after fighting for a few years, and they
made the English army go away, and after that, they were not English colonies
any more, they were the United States of America.