A legal document is a document that states some contractual relationship or grants some right. It must be signed by both parties and is binding on both parties. If it creates an interest in real...
Anything that you have to do by law. To drive a car, by law you must have a license. It is a legal obligation. You are legally obliged to have a driving license to drive a car.
If you change a material fact (any statement that can be confirmed or refuted) and attempt to pass the document off as fact then you are guilty of fraud. You could also be guilty of identity theft,...
It depends on the country and in the USA, it depends on the state. If you hold yourself out to be husband and wife in some states, your "common law" marriage can be legally recognized by a court....