Both parties must be present. You need an ID with your birthdate, $28.00 and you need to know your social security number. If you do not have a social security number, you must go to the social security office and get a letter from them stating why you do not have a number.
If you are under the age of 18yrs., one parent must sign an affidavit authorizing the marriage. If you are under the age of 16yrs., you must have a judge's permission authorizing the marriage.
Marriage licenses do not have a waiting period or expiration date. You can get a marriage license in any county in Idaho and get married anywhere in Idaho. The license will be recorded in the county in which you purchase it.