Description
Unable to see conditions tab on Workflow properties.
Cause
User might have have selected the table as "sc_req_item" in the workflow properties.
You can't write a condition for Requested Item table in the workflow. Condition won't work and is not required for the requested item.
Resolution
Remove the table name as "sc_req_item" in order to write the condition.
Additional Information
Documented here - Workflow properties