Hello and welcome to Apple Support Communities iPrachi,
We see that FaceTime is not working on your iPhone after updating the software on your iPhone. We know that it is important to have your iPhone working properly, and we'd be happy to help.
Take a look at the article below with some troubleshooting steps to help with what you've been experiencing.
If you can't make a FaceTime call on your iPhone, iPad, or iPod touch
If the issue remains, respond back with the answers to the following questions.
- If you restart your iPhone, does the issue remain?
- Do you have a pending update for the WhatsApp app in the App Store?
- Are you using the latest version (14.0.1) of iOS 14?
We look forward to hearing back from you.
Have a great day!