Yes, Vivo V11 Pro does have the App clone support. You can run multiple social media and WhatsApp accounts.
Yes, Vivo V11 Pro does have the 3.5 mm headphone jack.
Yes, you can purchase Vivo V11 Pro via without credit card option. Check out this video - this will help you to understand the whole process.
Vivo V11 Pro is made of industrial grade polycarbonate material.
The Vivo V11 Pro is a solid all-rounder at Rs. 25,990 and offers better value than the Oppo F9 Pro (Review), but for a bit more money. Think of it as a Vivo X21 with a bigger battery and better front camera, but at a much more reasonable price, which is a good recipe.