affidavit
written sworn statement of fact voluntarily made by an affiant or deponent under an oath or affirmation administered by a person authorized to do so by law
en-US/ˌæfɪˈdeɪvɪt/
en-GB/ˌæfɪˈdeɪvɪt/
written sworn statement of fact voluntarily made by an affiant or deponent under an oath or affirmation administered by a person authorized to do so by law