To prevent losing all your WhatsApp data, you gotta back dat app up.
WhatsApp uses iCloud to backup your chats to the cloud. Your chat logs and account data are secure in case you ever ever lose your phone and need to pick back up where you left off. Recommend: You can use Syncios Free iOS manager to backup all your iPhone/iPad/iPod messages, contacts, call logs, photos, apps and more for totally free. Get rid of iTunes entirely! Learn more from here.
How to turn on iCloud Drive fro WhatsApp backups on iPhone
First off, you'll want to confirm that you've got iCloud turned on and set up to back up WhatsApp data.
1. Launch Settings from your Home screen.
2. Swipe up to scroll down the menu until you see iCloud.
3. Tao on the iCloud button.
4. Tap on iCloud Drive button.
5. Tap the turn iCloud drive on if it is off.
6. Ensure that iCloud access for WahtsApp is turn on. Apps are list in alphabetical order, so WhatsApp should be near the end.
How to back up your data to iCloud
1. Launch WhatsApp from your Home screen.
2. Tap on Setting. It's the gear icon in the bottom right corner.
3. Tao the Chats button.
4. Tap on Chat backup.
5. Tap Back up Now to upload your chat data to your iCloud Storage.
If you'd prefer to set up iCloud automatically store your data, you can do so on this screen.
1. Tap Auto Backup.
2. Tap the backup frequency you'd prefer. Your options are Daily, Weekly and Monthly.
3. Tap Chat Backup to go back to the last Setting menu.
4. Tap the switch next to "include videos" to toggle whether or not to backup video messages.
Now that everything's backed up, you'll be able to restore your chats if you reinstall WhatsApp on any iOS device. If you want to migrate your data to a new phone, you will have to make sure everything is backed up to iCloud first. Then when you are going through the WhatsApp set up process on you new phone, simply restore your chat history when prompted.