I'm wondering if I can open up a local shop and sell bitcoins for cash without paperwork or signing anything. Sure a bitcoin ATM can fulfill that role but as a shop I could do other things such as sell bitcoin merch etc, offer information on bitcoin and cryptos etc, but primarily I'm wondering if I can sell bitcoin for cash without hassling customers with paperwork. I suppose the laws would be the same for an ATM machine? which I haven't heard to be of a legal problem. I'd be considering doing this in Texas, USA, by the way. Any references or shared knowledge would be great, and I'm less interested in speculation. Thanks!
You should be extremely cautious when doing that. Delve into the law of your country and prepare. Many anti-money-laundering offices see bitcoin as an effective means of hiding and secretly transferring large amounts of illegally obtained value.