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

CodeDisplayDefinition
send-message Send a messageThe action indicates that a particular message should be sent to a participant in the process.
collect-information Collect informationThe action indicates that information should be collected from a participant in the process.
prescribe-medication Prescribe a medicationThe action indicates that a particular medication should be prescribed to the patient.
recommend-immunization Recommend an immunizationThe action indicates that a particular immunization should be performed.
order-service Order a serviceThe action indicates that a particular service should be provided.
propose-diagnosis Propose a diagnosisThe action indicates that a particular diagnosis should be proposed.
record-detected-issue Record a detected issueThe action indicates that a particular detected issue should be recorded.
record-inference Record an inferenceThe action indicates that a particular inference should be recorded.
report-flag Report a flagThe action indicates that a particular flag should be reported.
<status value="active"/><experimental value="false"/><date value="2020-12-28T16:55:11+11:00"/><publisher value="HL7 (FHIR Project)"/><contact><telecom><system value="url"/><value value="http://hl7.org/fhir"/></telecom><telecom><system value="email"/><value value="fhir@lists.hl7.org"/></telecom></contact><description value="Provides examples of actions to be performed."/><jurisdiction><coding><system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/><code value="001"/><display value="World"/></coding></jurisdiction><caseSensitive value="true"/><valueSet value="http://hl7.org/fhir/ValueSet/action-code"/><content value="complete"/><concept><code value="send-message"/><display value="Send a message"/><definition value="The action indicates that a particular message should be sent to a participant in the process."/></concept><concept><code value="collect-information"/><display value="Collect information"/><definition value="The action indicates that information should be collected from a participant in the process."/></concept><concept><code value="prescribe-medication"/><display value="Prescribe a medication"/><definition value="The action indicates that a particular medication should be prescribed to the patient."/></concept><concept><code value="recommend-immunization"/><display value="Recommend an immunization"/><definition value="The action indicates that a particular immunization should be performed."/></concept><concept><code value="order-service"/><display value="Order a service"/><definition value="The action indicates that a particular service should be provided."/></concept><concept><code value="propose-diagnosis"/><display value="Propose a diagnosis"/><definition value="The action indicates that a particular diagnosis should be proposed."/></concept><concept><code value="record-detected-issue"/><display value="Record a detected issue"/><definition value="The action indicates that a particular detected issue should be recorded."/></concept><concept><code value="record-inference"/><display value="Record an inference"/><definition value="The action indicates that a particular inference should be recorded."/></concept><concept><code value="report-flag"/><display value="Report a flag"/><definition value="The action indicates that a particular flag should be reported."/></concept></CodeSystem>