This code system http://hl7.org/fhir/payment-issuertype defines the following codes:

CodeDisplayDefinition
patient PatientThe patient or a party issuing payment on behalf of the patient.
insurance InsuranceAn insurer, or party acting on their behalf, which is making payment following a contract, direct or indirect, with the patient to pay for healthcare-related services.
<status value="active"/><experimental value="false"/><publisher value="FHIR Project team"/><contact><telecom><system value="url"/><value value="http://hl7.org/fhir"/></telecom></contact><description value="This value set contains codes for the type of payment issuers."/><jurisdiction><coding><system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/><code value="001"/><display value="World"/></coding></jurisdiction><copyright value="HL7 Inc."/><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/payment-issuertype"/><content value="complete"/><concept><code value="patient"/><display value="Patient"/><definition value="The patient or a party issuing payment on behalf of the patient."/></concept><concept><code value="insurance"/><display value="Insurance"/><definition value="An insurer, or party acting on their behalf, which is making payment following a contract, direct or indirect, with the patient to pay for healthcare-related services."/></concept></CodeSystem>