• To edit or delete any particular contact, Click on Contacts.
• Click on the pen icon that says ‘edit.’
• Check the contact boxes that you wish to edit or delete. 
• Click on the delete icon after checking the contacts that you wish to delete from the list.
• Confirm the delete action by Clicking on ‘Yes’ on the alert popup.
• Click on the Save sign for saving the changes after editing or deleting the contact

You can either delete the customer contact or vendor contact by following the same procedure.