From Setup, configure a default No-Reply address from the Organization-Wide Addresses page. Add an email address in Special Purpose Organization-Wide Email Addresses, then follow the steps outlined in the verification email sent to the new default No-Reply address you configured.
Full Answer
How can I improve Salesforce Mobile and lightning experience actions?
Make sure buttons for New Task, New Event, Log a Call, and Send an Email (not Send Email) are added to the Salesforce Mobile and Lightning Experience Actions section of the page layout. Make sure your users have permission to create new tasks and events, log calls, and send email.
How do I configure a no-reply email address in Salesforce?
From Setup, configure a default No-Reply address from the Organization-Wide Addresses page. Add an email address in Special Purpose Organization-Wide Email Addresses, then follow the steps outlined in the verification email sent to the new default No-Reply address you configured.
Why can't I send email in Salesforce mobile & Lightning?
If the 'Access to Send Email' level in the organization is set to 'No Access' or 'System Email Only, in the layout, for "Mobile & Lightning Actions", users can drag and drop the Email button to "Salesforce Mobile and Lightning Experience Actions", but won't be able to save.
Why doesn't the 'send email' button appear in the 'activity' list?
There are a number of reasons why the 'Send Email' button may not appear in the 'Activity' related list even after it has been added to the page layout. First, Users should check if the 'Access to Send Email' level in the Organization is set to 'No Access' or 'System Email Only'.
Activity Timeline
When you look at a record in Salesforce Classic, such as a contact or opportunity, you use the Open Activity and Activity History related lists to stay on top of activities.
Recap the Latest Activities
Your colleague is out of the office, and you’re handling their accounts until they get back. When a client calls, how do you get up to speed on what’s been happening?
Find the Activities That Matter Most
If you’ve been working with an account, opportunity, or other record for any length of time, you probably have a mix of activities in the activity timeline. How do you find the details you’re looking for?
Tasks and Task Lists
There’s no Tasks tab in Salesforce Classic beyond the My Tasks list on the Home page.
Keep Your To-Dos Up to Date
Another great aspect of the task list is that while you see the list on the left, expanded details appear to the right for whichever task you have selected.
Calendar
Salesforce Classic includes a calendar to help remind you about appointments.
View Other Calendars
What’s especially helpful in Lightning Experience is how you can share your calendar and view your colleagues’ calendars from your calendar. Plus, you can add multiple calendars at the same time with user lists. If you don’t see user lists as a search category in the Add Calendars dialog box, ask your admin about setting up user list calendars.
