EHR -> that is going to be electronic health records systems. There is several different ways you can use that to input patient information in the system ( I actually use some of the systems when billing information to the patient or provider).
We use this in a digital format, then this information is shared with other providers within the health care system, also other insurance companies that the patient might have as long as they are coordinating with their primary insurance. EHR systems are usually handled through another vendor as well.
The most common way to collect patient information is by the medical charts. This information is sent over to input in the EHR system, such as medication, patient history, allergies, etc. This information is updated every time a patient visits a provider to keep the information updated, this is why the providers (doctors and nurses) use charts to have that information updated, the same as when a billing and coding agent asks for insurance information as well.