To create a backup of your filtered media files on WhatsApp, you must enable the backup feature on your WhatsApp settings. To do this, tap on the three dots icon at the top right corner of the screen and select “Settings”. Then, tap on “Chats” and select “Chat backup”. This will allow you to backup your chats and media files to Google Drive or iCloud, depending on your device. You can also choose the frequency and the network of your backup.