from postman if I invoke the an IP which goes through API Management I set
Ocp-Apim-Trace : True
. Will I be able to see the trace some where. Is this only ment to be used from inside the Test tab in API Management in azure portal?
Yes, if you include the Ocp-Apim-Trace header with a value of true, a link to the trace file will be returned in the response header Ocp-Apim-Trace-Location, which you can open via Http
Pulling Vitaliy's comment up into the answer: the APIM subscription key needs to belong to a user who has admin rights in order for this to work