WhatsApp on iOS backs up the chats to Apple’s iCloud service. This is a good thing since iOS devices typically rely on iCloud to sync their data, plus it also syncs with Mac computers. However, it should be noted that the backups stored on Apple’s servers are not necessarily encrypted.
This means that in the event of a law enforcement request, Apple could in theory hand over your WhatsApp data. However, WhatsApp is hoping to fix that because according to the latest information from WABetaInfo, the company is continuing to work on creating a password protected encrypted iCloud backup.
• The chat database is already encrypted now (excluding media), but the algorithm is reversible and it's not end-to-end encrypted.
• Local Android backups will be compatible with this feature.
The chat DB and media will be encrypted using a password that only you know. https://t.co/WAliLUnF18
— WABetaInfo (@WABetaInfo) March 8, 2021
This means that even if there are requests from law enforcement, Apple cannot hand over the data, or rather even if they did, it would be useless because it would be encrypted and only the owner will have the password to it. WhatsApp already offers end-to-end encryption for its chats, but its backups are a different story, so this feature could change that.