Click the "End user instructions" field and add instruction the user

Click the "Ticket form title" field to enter the name of the new form.

Click the "Title shown to end users" field to enter the form title visible to the users

Click the "+" icon to add new fields to your ticket form. 

Start a new ticket and click on the "Form" to choose which form to use

Fill in the form-specific fields, such as priority, type and tags

Click "Submit as Open" and you have successfully created a new ticket using a custom ticket form

Customizing Ticket Form in Zendesk