When you’re talking about “Patient documents” are you talking about PDFs or CDAs, are you talking about FHIR Documents (Bundles starting with a Composition resource) or are you referring to patient-centric resources in general (e.g. AllergyIntolerance, Observation, MedicationDispense, etc.)?
Are you wanting to post everything at once? If so, you should look at the transaction capability on the REST page. Otherwise, you can POST to the different endpoints for each resource. In terms of retrieval, to get everything for a patient, you can use the Patient/$everything operation. You can also query individual endpoints.