“We have access to all kinds of personal information about the patients.”
You work at a doctor's office. You're talking to a member of your extended family about your job. You want to express how serious your responsibilities are at work, so you talk about the information that you are able to see there.
We have access to all kinds of personal information about the patients.
To "have access to" something means that you are able to see it or use it. For example, if you "have access to the Internet", it means that you are able to connect to the Internet and use it. Here's another example:
"All kinds of ___" means "a lot of different kinds". In the example at top, it sounds like the speaker is able to see a lot of information about patients, including very personal information.
"Personal information" is information about you such as your phone number, address, age, photos, bank account number, and so on. People usually want to keep their personal information secret.
You usually express whose personal information you're talking about with "___'s personal information":
But in the example at top, this wouldn't work because the adverb phrase "all kinds of" comes before "customers'". If you tried to use the phrase "all kinds of customers' personal information", it would seem like there was
People who visit and use a doctor's office or hospital are not called "customers", but rather "patients".