This may seem elementary but getting married is a legal process. You MUST have a valid marriage license to be legally married in any and every state. The marriage license can only be obtained from and issued by a marriage bureau in a county of the state in which you live. The Minister, Reverend, Pastor, Judge, Rabi or ordained wedding officiant CANNOT issue a marriage license. Generally a marriage license can be obtained in any county of a state and used in any other county in the state but you must confirm this information with your particular state. Many jurisdictions have different rules.
It is also important to note that marriage licenses cannot cross state lines. For example, you cannot use a NJ license in PA or any other state for that matter or vice versa. Marriage licenses are specific to the state. Most states do not have a residency requirement to be married there. However, you do need to apply for the marriage license in the state where you intend to be married.
When planning your ceremony and applying for your license, it is important to know that some states have a waiting period. This means you cannot use your marriage license right away. In PA the waiting period is 3 days. Some states have no waiting period like NV. Again, check with your particular jurisdiction to learn how soon your license will be valid after it is issued. Marriage licenses also expire. They are not good indefinitely. In PA a marriage license is valid for 60 days. Again, check with your local marriage bureau to see how long a marriage license is good for in that state. If the license expires, you will have to start the entire application process over and pay again. Please note that an officiant is not permitted to marry any couple that does not have a valid marriage license. Period. Nothing would be worse than reaching your wedding day and being told you can't get married because your license is not valid. Give yourself plenty of time to check and confirm this information.
Some states require witnesses to the marriage and require them to sign off on the license together with the couple, others do not. Witnesses are not required in PA if the couple is married by someone authorized to perform marriage ceremonies. However, Pennsylvania is a Quaker State. This means couples are actually permitted to marry themselves here. A marriage license is still required but a different type of license is issued. It is called a Self-Uniting License. This type of license does require two witnesses to sign the license in addition to the couple. All of the other rules regarding waiting periods and expiration dates are the same.
If you are getting married in Pennsylvania, below is a list of the most popular counties. As you read, you will notice each counties requirements differ. Some counties are cheaper than others, some include the certified copy in the cost, others require you to order and pay for it later. In fact all the licenses all look different too. However, in the end, no matter which county you obtain your license from it will be accepted in any other county in the Commonwealth of Pennsylvania.