Usually, WhatsApp does its Daily backup at 4:00 am Every Day so you have to wait until 4 am or you can Simply initiate it by tapping the Backup now option located on Top. The backup now Option will automatically create a local backup in your Phones internal Memory or SD card up and Send the Chat Data to Google Drive.
Once WhatsApp Started to backup you can’t stop the Process. If you have sent and received lot of media in Conversations the backup Size will be Quite Large, So be aware of that otherwise you will overuse your Data Usage.
When you Use WhatsApp on a new Phone, after you sign in with your mobile number, WhatsApp will check to see if there is any local backup or Google Drive Backup for your Account. If it found any backup Data the App will ask you to restore the Data from Drive or Local memory.
# WhatsApp’s local backup and Google Drive Backups are incremental, which means you can’t decide what to Backup.
# Your WhatsApp Backup Data is Hidden in Google Drive, to view the Hidden WhatsApp backup Open google Drive on Web, go to Settings > Manage Apps and WhatsApp will be listed as having hidden Files.
# WhatsApp doesn’t backup Videos, only Images and Chats