https://www.opennotes.org/onc-federal-rule-interoperabilty-information-blocking-and-open-notes/#:~:text=The%20program%20rule%20on%20Interoperability,healthcare%20provider%20beginning%20November%202Here is a good explanation of the types of information that will be available online from your medical records. When I look at my records in MyChart, I see the exact same progress notes that are prepared by the clinician for the medical record. I can either see the progress notes or the AVS: the after visit summary, which is a summary of the visit that we print off and hand to the patient as they leave.
What Jocassee says regarding each major EHR having their own portal is spot on. Generally speaking, you log into the website of your healthcare provider and access the internal chart portal from there.
The major exception regarding records that will not be available are psychotherapy notes, which can in some circumstances be withheld from the patient if doing so causes danger to the patient or others. This is no different than current standards for paper or electronic records.
PS: I have for years been a proponent of giving patients their actual medical records upon request, and did several pilot projects on this under the OpenNotes banner. It is my opinion based on my experience, that patients have a better understanding what is going on, are more likely to follow medical advice, and have fewer questions afterward. The VA was one of the early adopters of this concept with the Blue Button, and it was their positive experience with this that helped bring others along into the fold.