Your WhatsApp messages are automatically backed up and saved daily to your phone's memory. Depending on your settings, you can also periodically back up your WhatsApp chats to OneDrive. If you uninstall WhatsApp from your phone, but don't want to lose any of your messages, be sure to manually back up or export your chats before uninstalling.
If you want to restore the backup, please read this article.
If you would like to keep a record of your messages on a computer or in an email, you can email yourself individual chats. Please follow these steps:
* It is not possible to attach chat media in the email at this time.
* Your chat history will be attached to the generated email as a .txt file (Windows Phone 8.1 and later) or pasted into the body of the email (Windows Phone 7 and 8.0).
* You may not be able to email your entire chat history due to Windows Mail size restrictions. The only way to export newer messages would be to delete older messages and then email your chat history again.