So I moved home to Wisconsin today and got a PO box so my Aunt and Uncle don't know I have credit cards. But I have a question.
For the PO box address when I update my address on my credit card sites do I do it as PO box *** then the city state and zip. Or the post office address PO box and then city state and zip. Whoever knows can you post an example as well? Thank to all so much
If you want to know how to format the address, you'll want to start here:
https://tools.usps.com/go/ZipLookupAction_input
The only time you can use the street address of the Post Office is if you subscribe to their 'Street Address Service'. It's free (where available), and it allows you to use their street address plus your P.O. Box number as the "unit" for package delivery. I subscribe to the service and it generally works well, especially for packages that are start off as UPS or FedEx and end up with the 'last mile' being USPS anyway (like SurePost or SmartPost). For packages that are 'traditional' UPS it can be a mixed-bag, since tracking ends once the item is signed for by USPS personnel.
The form you have to complete for this service explicitly states that you're not to use it as a 'residence', so that would prevent you from being able to use as your primary address on credit cards (the PATRIOT Act requires banks to know your home address). Some companies, such as Amex, allow you to give your home address and separately list a mailing address, which sounds like would be suitable for your situation. Note that you might be able to get creative and "shoe-horn" a P.O. Box address into the address field (and get the creditor's system to accept it), but to me it wouldn't be worth the possible headache later on (I don't advocate this, but I mention it since you alluded to it anyway).
I don't have any knowledge of private post office services, but it's worth checking into and very well might be your best option. At the risk of sounding like a 'fuddy-duddy' I'll just say to be mindful of their policies. Personally I would see about getting e-statements, which would take care of most of the credit card mail anyway. I'm away from my "home" address much of the time, but thanks to the internet it doesn't matter. 
@Anonymous wrote:I love my PO box and use it for mailing address on all, or nearly all, of my credit card accounts mailing. Never any issues. Private boxes probably ok too, but once you get everything setup its a pain to change everything so I just stick with my PO box. Even though they seem to raise the price every year it's still reasonable and I like supporting the USPS.
+1... I've been pleased with my USPS P.O. Box as well. 
Something else to consider if going the private route (CMRA) is that mail forwarding can work differently (for when you move or no longer need the box).
When I was doing my checking around a few years back I found that in most cases the forwarding is handled by the CMRA and not the USPS, and that they can and often do charge for the service where it would be free with the USPS.
This could be YMMV, but it's worth figuring out now rather than after the fact, since during a move the last thing you want to be concerned with is losing your mail.