If you back up WhatsApp chat history on Android, it will be stored in Google Drive. For iPhone users, WhatsApp message backup will be saved in iCloud.
If you use FonePaw WhatsApp Transfer for iOS, it will be stored on the local computer or other removable drives. Normally the path is ...(user's name)\Documents\FonePaw\FonePaw WhatsApp Transfer for iOS\Whatsapp\...
If you want to change the storage path, follow the guideline.
1. Click the Menu icon on the right top corner of the homepage.
2. Go to Preferences.
Here, it enables you to select the output and backup path. You can also agree to update automatically if you want.
3. Choose OK in the end.