Sometimes email providers block attachments. So saving VCF backup file to your computer via Wi-Fi is the only option for users not using iTunes.
You can save backup file to your computer if your iOS Device (iPhone, iPod Touch or iPad) and your computer (PC or Mac) are in the same local network.
To access backup file from your computer please first connect your iPhone or iPad to Wi-Fi and enable "Wi-Fi Manager" option via in app Settings page.
Then type the url (on settings page) into address box in your browser on your computer to download backup file.
Please keep this backup file after saving it on your computer. If you need to restore your contacts, you can upload your backup file via “Wi-Fi Upload” page to your device and restore it using “In App vCard Restore” option.