The primary writer of the declaration of independence was Thomas Jefferson with help from Benjamin franklin, John Livington, and John Adams and many others.
The colonist felt like they were imprisoned and had no say about anything, also the natural rights, liberties, and freedoms were ignored by the king. So they wrote the declaration to declare independence from Britain.
It said that the colonist were done with Britain and the delusional king. It said that all men are created equal and they are endowed by their creator certain unalienable rights, that among this are life, liberty, and the pursuit of happiness.