You can create a button on your app content for your users to simply click on it to enable receiving push notifications from your app.
1. Admin > Content > Customize. Click to edit your app.
2. In the app customization, expand the group, 'Interactive buttons' under Content. Click on Enable Push.
3. Set up the button to enable push.
General tab: The General tab is selected by default. You can give button a friendly caption in the 'Name, title or heading' field
Icon tab: Select an icon for the button here
Color tab: Choose your color for the button
Size tab: This is the size of the button on your content
4. Click on the 'Create' button to complete creating the button.
5. Put online' to publish your new changes in the content so that it will appear on your users' devices. The 'Put online' button's caption changes from 'Put online' to 'Published' once the changes have been applied successfully.
Your button appears only on the mobile apps. It won't appear when you simulate content using 'Try It'