Update: Microsoft Dynamics 365 for Financials has been rebranded to Microsoft Dynamics 365 Business Central.
In this example, we are going to add a new contact to our existing Vendor, London Postmaster.
Step 1 - Click the ellipsis and select edit.
Step 2 - In the ribbon click on Contact
You should now see a list of contacts associated with your vendor. The first record which is in bold, is the company contact and contains all of the primary contact information.
Step 3 - Click on New and this will open the Contact Card. You can now enter your contact's information.
Step 4 - Once you have finished entering your information hit the X and this will save your information and close the Contact Card.