A mail group allows you to email a group of people without having to individually select each email address. The following are directions on how to import a spreadsheet of email addresses into your Gmail address book. In order to add a mail group to your e-mail contact list, you must first be signed in to your Gmail account.
1. Create a spreadsheet (using Excel or Google Spreadsheet) of email addresses into your Gmail address book.
2. Once you have created your spreadsheet, go to File → Download As → Comma Separated Values (CSV file).
3. A Comma Separated Values (CSV) file will automatically save to your downloads folder, or you can save the file on your desktop or documents.
4. Go to your Gmail account and click on Gmail in the upper left hand corner. Click on the drop down menu and select Contacts.
5. Click More and select Import.
6. A window will pop up, and then click on Choose File. Import the CSV from where you saved it (downloads, desktop, or documents).
7. Once the file is selected; Click Import.
8. Click Find & merge duplicates, so that you can merge duplicates.
9. The group name will automatically be Imported and the date it was imported. To change the group name, select the group from the left sidebar. Then, Click More → Rename group. Select a group name and click OK.
Your mail group has now been created and you can send an email to all those in the group by typing in the group name.