Extracting Hashes

Hi,

I've been lurking around trying to learn how to use Hashcat and I have had some success using the actual program. The point at which I struggle is acquiring password hashes. 

I have found some python and perl scripts for John the Ripper that work sometimes but was wondering if someone could tell me what the most commonly used methods for extracting hashes are.

I spoke to someone that says they look up on the internet at which byte hashes are located and then navigate there using hex editors. Is this how you guys do it? 

Thanks for the help ppl.