Please find the below code to auto submit workflow through X++ code. here you can just change the table name based on the functionality you are working. in my case I have used ProjBudgetRevision.
//Check whether we have a Active workflow on the table.
WorkflowVersionTable workflowVersionTable = Workflow::findWorkflowConfigToActivateForType(workFlowTypeStr(ProjBudgetRevision),
projBudRevision.RecId,
projBudRevision.TableId);
//If workflow is active then submit the workflow.
if (projBudRevision.RecId && workflowVersionTable.RecId)
{
//submitting to workflow
Workflow::activateFromWorkflowType( workFlowTypeStr(ProjBudgetRevision),
projBudRevision.RecId,
"@AutomaticWorkflowSubmit",
false,
curUserid());
//Update revison workflow status to submit
ProjBudgetRevision::updateProjBudgetRevisionStatus(projBudRevision.RecId, ProjBudgetRevisionWFStatus::Submitted);
}