Manipulating entity records in your server-side customization can be done using early bound or late bound classes. Early bound classes allow you to use Visual Studio intellisense and dot notations to access and validate entity names and attribute names at compile-time. On the other hand, with a late bound entity, a developer will have to type the entity and attribute's names manually which will be validated at runtime. Nonetheless, late bound entities have an advantage; they give you the flexibility to write generic code unbound to specific entities and attributes.
In order to generate early bound entity classes, you will need to download a version of the Dynamics 365 SDK that matches your Dynamics 365 instance. You will also need an active Dynamics 365 user with System Customizer or higher privileges.