Can I trigger a workflow approval or reject externally?

I am using powerapps quite effectively pulling data from PDM and populating some apps. I would like to expand the capability of one of my apps by providing an approver the ability to approve or reject a PDM object inside of the app. Is this possible?? The actual mechanics of writing the app is not the problem. It would be the outside connection to do it. I have many ways that I can send data out of my app. Here are some options:

  • Email
  • SQL
  • Sharepoint
  • etc

Ideas?

SolidworksApi/macros