Your insurance agent/broker needs to tell you that; there's no universal process for every insurance company or agency. Usually when you renew your policy you will get a copy of the policy itself, but if you want to request a certificate of insurance as proof of coverage for someone, and especially if they want to be an additional named insured, there are set procedures you need to follow to make the request. There is usually no charge for obtaining a certificate of insurance.
Your PTO certainly does need insurance. Although you are doing your activities on school grounds and with the approval of the school, if anyone gets hurt, sick or is picked up by the wrong adult, the PTO is responsible and liable. You need to protect your assets as well as those running your events against any bills or lawsuits that may arise as a result of neglect or mishap.
We had a child break a finger on an inflatable and the parents stated that we should have had more than one adult supervising it. Luckily, they did not sue and they didn't ask that we pay the ER bills, but they could have. We learned quickly to make sure everything was properly supervised, food prepared properly and avoided potential hazards at each and every event.
Can any one help me understand the purpose of insurance? My VP just asked me about it and if we would consider it. I would love to just would like to know a little more personal info on it. Does anyones school or district cover their insurance?