Open WhatsApp
Tap the three dots or Settings
Go to Chats
Tap Chat backup
Tap Back up to Google Drive or Back Up Now
Choose your Google account
Select backup frequency
Choose whether to include videos
Make sure you are connected to Wi-Fi
Wait for the backup to finish
On iPhone, go to WhatsApp Settings
Tap Chats
Tap Chat Backup
Tap Back Up Now
Make sure iCloud Drive is enabled
Ensure you are signed in to iCloud
Keep enough storage available on your phone and cloud account