Greetings MayureshA,
Thanks for visiting the Apple Support Communities! It seems you'd like to change the contact options to your WhatsApp contacts on the share sheet when sharing a photo. Additionally, it seems you'd like to change the order of the different sharing options on the share sheet.
Customizing the contacts to show your WhatsApp contacts is not an option for the share sheet. You're welcome to leave feedback to Apple at the following website: Product Feedback - Apple
To change the order of the sharing options on the share sheet, swipe to the right of the sharing options and tap More. After tapping More, tap the Edit button in the top-right corner. From there, you can then rearrange the sharing options.
Kind regards.