You want to push the URL of your iGrafx platform to your iGrafx Desktop Client users (i.e. Flowcharter), so they can pick it from the list of known URLs?
This can be done when you use your own "Administrative Installation" or any other method available in your software deployment tool. Your custom installation files (MSI) or software deployment will need to include the information for the URLs. They are stored in the registry below the following key:
Use a standard installation and connect to your iGrafx Platform instance, then check the values for under the above provided key.