Q: while installing whatsapp its appearing disebled

Hello rnt0589,

Welcome to the Apple Support Communities!

I understand that an app from the App Store, WhatsApp, is not working as expected. To troubleshoot this situation, I would recommend reading over and working through the information and steps located in the attached article below. 

If an app you installed unexpectedly quits, stops responding, or won’t open - Apple Support

Have a great day