ISV.Config is an XML file used to add custom menu items and controls to the toolbars. This file used to add shortcuts on an entity Form which is not CRM entities to other web applications or interfaces. It is intended to be used by Independent Software Vendors (ISVs) who want to add extra features to CRM.
It needs to be exported to be modified and then reimported to the system to be updated.
The following code illustrates the ISV.Config main nodes structure:
Each entity has its own menu items and toolbar, so to add a custom menu item or button to that particular entity, open the file with any text editor to customize it.
Do a find for Custom Entities section and use the code below inside existing file for user defined entity.
Save the changes and import the ISV.Config file to go to Settings, Customizations, Import Customizations, upload the modified xml file, and click the Import Selected Customizations.