Creating a form

In this recipe, we will create a form, which will be accessible from a menu path. This will involve creating a route that tells Drupal to invoke our form and display it to the end user.

Forms are defined as classes, which implement \Drupal\Core\Form\FormInterface. The \Drupal\Core\Form\FormBase serves as a utility class that is intended to be extended. We will extend this class to create a new form.

Getting ready

Since we will write the code, you will want to have a custom module. Creating a custom module in Drupal is simple: create a folder and an info.yml file. For this recipe, we will create a folder under /modules in your Drupal folder called drupalform.

In the drupalform folder, create drupalform.info.yml. Drupal will parse the info.yml file to discover modules. An example of a module's info.yml file is as follows:

name: Drupal form example 
description: Create a basic Drupal form, accessible from a route 
type: module 
version: 1.0 
core: 8.x 

The name will be your module...