Quick Answer
A Dynamics 365 plugin is a custom .NETassembly that extends the platform with business logic beyond its standard capabilities. To create one, developers typically build a C# class library, add the required Dynamics 365 SDK packages, write and compile the plugin code, sign the assembly, and register it in the appropriate Dynamics 365 environment. Plugins can automate processes, respond to specific events, and support business requirements that standard features cannot handle.

