I don't know much about bitcoin so forgive me for the ignorant title and terminology. My mom recently got into bitcoin and told me she was investing her money in it or something like that and she's been doing these transactions through a company (whom I referred to as "middle men" in the title). These middle men recently asked her to provide pictures of her passport with her in it hold it up and also a pic of her credit card bill with her in it as well ; apparently to verify that she's a resident where we live (in Hong Kong, China).
I thought it was a bit suspicious that they asked for such private information. Is this a normal practice of bitcoin middle men/compamies?