1. Go into a contact and click on the Edit button as shown below in red: 

2. This will take you to the contact information i.e. name, address, phone number etc. 

To the bottom right is where you enter all the phone, mobile and communication details. There is also an option for website address - click on the drop down:

3. Select Website address from the drop down. In the blank box next to it enter the website address - such as www.bbc.co.uk (as an example):

4. Then click on Update button.

5. When you go back into the contacts record you will see in the contacts business card section on the right-hand side of the screen the website address will be displayed and you can click directly on the address to take you to the contacts website.