In this article only for how to create field dependency in salesforce so Let’s begin. before creating filed dependency you mutch have some know the answer for the following questions.

1. What isField Dependency?
2. How to create field dependencies in Salesforce?

What isField Dependency?

Field dependencies are some special type of controller that help us to change the content of a particular field based on some field input.
For example, Just imagine we have two picklists filed one is Country another one is City. Here we are going to change the City values based on Country picklist input.

So Here

Controlling Fields – Country
Dependent Fields – City

Controlling Fields: It controls the available values in one or more dependent fields.
Dependent Fields: It’s able to display the output based on the input selected for the controlling fields. In the case of the above example, the country will be the controlling field and the city will be the dependent field. Controlling field is the picklist and here dependent field is always a picklist.

How to create field dependencies in Salesforce?

STEP 1: First create objects based on your business needs
STEP 2: Create fields in your object.
STEP3: Based on your fieldset you need to decide controlling field and dependent field.