You don't need to go to court to change your name but is the new name official? And can you change legal documents so that they have that name on it?

Your legal name is your legal identity. You can't change it except by a legal action.

If you live in a state in the US that allows you to "register" your common law marriage, then you have a document to use to have the name change.

The issue is to legally change you name for marriage, you have to provide SS and DL offices with copies of the marriage license. So to use this for common law, you have to provide a court document stating you are common law marriage

Also not sure of your location, most places no longer have common law marriage.

For better advice, where are you living, how many years have you been living in a common law manner, what evidence of common law is there,