Backing up your data is always important, including emails that are stored on someone else's server. If you use Gmail, making backup copies is a relatively straightforward process. In fact, Google gives you the option to back up all of your data at once, including your chat messages and even your Google Play e-books.
Another approach to getting your Gmail messages on to a computer is to sync your Gmail account with an email app, such as Outlook or Thunderbird.
Download an Email Archive File
Log in to your Gmail account, click your Profile icon in the upper-right corner and click the "Account" link. Scroll down the Account Settings page and click the "Download Data" link. Click the "Select None" button at the top of the Account Settings page, unless you want to download all of your Google-related data. By default, your Blogger blog posts, Google Drive files, photos, maps and all of the other download options are selected.
Scroll down to the Mail section and then click the "On/Off" button to select Gmail. Click the "Arrow" beside the On/Off button to see your download options. Using the default settings, Google will create a file with every single email, including spam. Click "Select Labels" and then click the "Gmail Labels" button. Labels are, of course, Google's name for folders.
Select the labels you want to download, such as your Inbox, Sent or Trash labels. Click the "Done" button. Select any other kinds of data you want to download. Scroll down to the bottom of the Download Data page and click "Next."
Click the "Delivery Method" menu and select whether you want the download link sent to your Gmail inbox, or to your Google Drive account. Google compresses the download file in .zip format, which can be opened in Windows 8.1 just by double-clicking it. You also have the option of receiving the file in .tgz or .tbz formats. Click "Create Archive." When you receive the link to the file, save it to your computer.
Sync Gmail with Your Client Mail App
Log in to your Gmail account and click the "Gear" icon in the upper-right corner. Select "Settings" from the drop-down menu.
Select the "Forwarding & POP/IMAP" tab and then click the "Add a Forwarding Address" button. Enter the email address you use on your email client app. For example, if you use Microsoft Outlook, use your Hotmail, Live.com or other Microsoft email account.
Review the email forwarding options. In most cases, you should use the default IMAP settings, which keep your Web-based Gmail client and your desktop client synced. However, if you prefer using the older POP protocol, you can select that option instead and decide if you want messages that you've read on your computer to be saved or deleted on the Gmail website.