For Gmail you will only need to setup one of the following options (Mail App through your device or Gmail App.)
Setting Up Gmail on your Mobile Device
To set up Gmail with the email app:
(Make sure to delete any other "Exchange" accounts on your device.)
In this example, we'll explain how to sync a Gmail account with the Mail app for iOS devices, including the iPhone and iPad. Keep in mind that this process may vary depending on your device.
The other benefits of using the official app is that it allows you to use all the features that Gmail offers such as labels, see Inbox categories like Promotions, Social etc, ability to respond to Google Calendar apps right from the app, edit email signature and vacation responses and more.
Set up the G Suite Training Chrome extension (formerly Training for Google Apps) to access interactive, self-paced G Suite lessons directly in your browser. This free extension adds a training menu for G Suite services, including the Google Admin console, Calendar, Classroom, Docs, Drive, Forms, Gmail, Google+, Groups, Hangouts, Sheets, Sites, and Slides. Within each service, you click G Suite Training to see relevant lessons. Each lesson is quick and easy-to-follow, with onscreen instructions and tips to guide you.
The extension is simple to use, making it an ideal way to learn about new features and increase G Suite usage in your domain.
Google App Launcher
The Chrome app launcher is an icon that is located at the top right hand side of the the screen within Chrome. This is a group of shortcut to get you to the most common Google apps.