Note: unfortunately, you cannot currently edit existing reports to add more email address. You will need to delete the old report and create a new report.
First of all you'll need to access the Exports & Reports section, which can be found at the bottom of your Analytics menu on the right hand side menu!
For a new report :
On the page "Create a new report", add the email addresses on the field "Email":
Once your report is generated, the email addresses you entered will appear on the "Scheduled exports and reports" table as 'Multiple recipients' (you can hover on the number to view the full list of email addresses):
For an existing report :
It's not possible to edit an existing export/report yet.
If you need to add one or several email addresses to an existing report, you will need to delete this report and create a new one with the same parameters and the email addresses you want.
Don't worry, you won't lose your exports history if you delete a report from the "Scheduled exports and reports" table!