You need to make separate Rest API calls for each folder separately.
Example 1:
Method: POST
URL: https://**ORCHESTRATOR_HOSTNAME**/odata/Releases
Headers:
X-UIPATH-OrganizationUnitId: FOLDER_ID_1
Content-Type: application/json
Accept: application/json
Body as JSON:
{"Name":"Test 1","Description":"Add a queue item","ProcessKey":"AddQueueItem","ProcessVersion":"1.0.1-alpha.55","EntryPointId":1207511,"InputArguments":"{}","SpecificPriorityValue":45,"JobPriority":null,"RobotSize":null,"ResourceOverwrites":[],"Tags":[],"ProcessSettings":{"ErrorRecordingEnabled":false,"Duration":40,"Frequency":500,"Quality":100,"AutoStartProcess":false,"AlwaysRunning":false}}
Example 2:
Method: POST
URL: https://**ORCHESTRATOR_HOSTNAME**/odata/Releases
Headers:
X-UIPATH-OrganizationUnitId: FOLDER_ID_2
Content-Type: application/json
Accept: application/json
Body as JSON:
{"Name":"Test 2","Description":"Add a queue item","ProcessKey":"AddQueueItem","ProcessVersion":"1.0.1-alpha.55","EntryPointId":1207511,"InputArguments":"{}","SpecificPriorityValue":45,"JobPriority":null,"RobotSize":null,"ResourceOverwrites":[],"Tags":[],"ProcessSettings":{"ErrorRecordingEnabled":false,"Duration":40,"Frequency":500,"Quality":100,"AutoStartProcess":false,"AlwaysRunning":false}}
Let us know if this helped.