Entity Framework best approach to used

1. Code first
In the Code First approach, we focus on the domain design or entities/POCO classes first and create classes as per our model requirement. We do not have the database of the application, rather we create database automatically from code after defining our domain.
No matter, you are not an expert in database, if you are a C# developer, just focus on your model/class creation. EntityFramework will take headache of creating and managing database for you.

2. Database first
To meet the needs of developers who want to derive a domain model from an existing database, database first approach provides a set of modeling tools that generate a domain model, validate a domain model, and create persistent classes based on the storage (database) model.

3. Model first
With the model first approach, you can design a model in a designer. Or you can simply define classes and let EF work with those—referred to as code first. Also in that approach EntityFramework will take headache of creating and managing database and classes for you.

End of the point this is clear if you have good command on database and already created database structure then you can choose database first, in other hand you have good command over the oop and coding and want to do everything by design model then choose Code first approach, and if you want to create very simple application and simple kind of database without any class model or database then you can choose model first.