Which access modifier should be used for primary methods to make them accessible from anywhere?

To ensure that primary methods can be accessed from anywhere within the application, the most appropriate access modifier is public. When a method is declared as public, it allows all other classes and objects to have visibility and access to that method, regardless of the package or assembly it resides in. This level of accessibility is fundamental when you want to create APIs or libraries that are intended to be used broadly by different components of a program or even by other programs entirely.

Using other access modifiers limits the method's visibility. For instance, private methods can only be accessed within the same class, protected methods are accessible only within the same class or subclasses, and internal methods are limited to the same assembly. By choosing public, you are providing the widest possible access to the method and ensuring that it can be called from any part of your codebase.