You can back up and restore your WhatsApp chat history with iCloud.
You can make a manual backup of your chats at any time.
Go to WhatsApp Settings > Chats > Chat Backup > Back Up Now.
You can enable automatic, scheduled backups by tapping Auto Backup and choosing your backup frequency.
This will back up your chats and media to your iCloud account. You can choose to include or exclude videos from the backup. The iCloud backup process can take a while to complete, depending on your Internet connection and backup size.
If you're concerned about your cellular data usage, we recommend that you limit your iCloud to only back up on Wi-Fi.
If you've previously backed up your iPhone using iCloud or iTunes, you might be able to retrieve your WhatsApp chats by restoring your iPhone from a previous backup. For more information on backing up and restoring your iPhone, visit the Apple Support website.
You can email yourself your chat history if you'd like to save a chat.
Note: If you're in Germany, you might have to update WhatsApp before you can use the export chat feature.