Can I add a "script' into existing collection in order to Upload external docs

I am using PM to load data into a monitoring platform. The collection I am using works correctly and delivers the information correctly. I am not a PM, JSON or API expert my any means. I now need to upload docs to the monitoring platform via PM. Is there a was for me to add some type of “script” to existing collection which will allow me to upload docs to the platform through PM?