Before you proceed, you need InTouchApp installed on your phone & InTouchApp Extension installed on Chrome or Firefox. Learn more.
How to Edit Contacts from WhatsApp Web:
Step 1 - Open web.whatsapp.com in the browser and scan the QR code by using WhatsApp on your mobile phone.
Step 2 - Select the contact whose contact information you want to edit.
Step 3 - On the Chat screen, beside the name of the contact, you will see a red pencil icon - Click on the same.
Step 4 - You will see a pop-up with the contact information already saved. Edit the information contact you want to about the contact. Once done, click on Save Contact.
The contact detail gets automatically updated and would be reflected in your phone contact book shortly.