How to create a custom app in Shopify?

To create a custom app in Shopify, foremost, you need to create a Shopify partner account. To create a new account, use this link, https://www.shopify.com/partners. Skip this step if you already have a Shopify account.

After that login your account
After login, click on app as shown in image below
Now click on create app
Now choose any one app type, here we will use public app.
After click on public app or custom app scroll down you will see the below screen.
After fill the above form click on create app or see the below image how to fill the above blank field.
Congratulations ! You have created your custom app successfully.