Send emails from Salesforce for Android and iOS

Some things to keep in mind:

• When sending emails from the native device, you can't use Salesforce Email Templates found in the full site.
• Emails sent are not sent out of Salesforce, and so they are not tracked or logged in the same way as other emails from the full site.
• Sending an email is not automatically added to the record in Salesforce for Android and iOS.
• The email button cannot be disabled. However it is hidden if the record does not contain an email address.
• The Send Email action (standard productivity action) is supported on Contacts, Leads, Users, and Person Accounts. Please see Salesforce Mobile App Action Bar and Considerations for Actions in the Salesforce Mobile App
• Custom Object Specific Send Email Actions are not supported and will not appear in the Salesforce App.
• For more details on the difference between the Salesforce App and desktop experience: Customer Service Features: What’s Different or Not Available in the Salesforce Mobile App
• Email tracking is not supported in Salesforce for iOS or Android. 

• Users can use 'Email to Salesforce Address' to log the emails in Salesforce. Please see How Does Salesforce Email Work?
• System Administrators can set up email integration. Please see Explore Email and Calendar Integration Products