Urban exploration

Okay I have a question for people who are more into the “legal urbex” like, getting a permit to explore a secret spot for example. 

How do you even get this permit ?? And what are the requirements? I’ve been exploring lost spaces for a while now, but i always have this background thought that’s constantly nagging my mind with what if I get caught?? Kinda makes me poop my pants ngl… 

I did some research and found out that you can actually do all that legally with a certain permission slip that you can show officers IF you get questioned, or caught by authorities. It doesn’t really get more into detail on how to attain it or where to attain it tho… 

Would appreciate some help here thanks