Your Shopify Domain is the text found after the URL of your store in the address bar. For example, in https://admin.shopify.com/store/6nzh0y-y6, the domain is 6nzh0y-y6.
You can also click on your profile in the top right corner, then select All Stores to view the list of stores associated with your account.
From the displayed list, your Shopify Domain is the value before myshopify.com.
In the modal window, enter the App name and select an App developer. The app developer can be the store owner, or any staff or collaborator account with the Develop apps permission.
Click Create app.
After you create a custom app, you can assign API scopes to it. A custom app can have Admin API scopes, Storefront API scopes, or both, depending on the requirements of the app. You need to select at least one scope before you install the app.
In the Overview tab, select at least a single scope from either Admin or Storefront API scopes, or both, depending on the app’s requirements.
Click Install app.
In the modal window, click Install.
Once your custom app is installed, your API Access Token will be generated.