Do not use the SIM to store your contacts since the fields available are limited.
By using the Hotmail entry (which is in fact your Microsoft account), you get access to all available fields.
Also, if you configured your phone to do so, everything gets synchronized on the cloud with your Microsoft account. If you ever have to reset your phone or change for another Windows Phone, everything gets synchronized automatically and you don't have to re-enter your contacts again. And, as an added bonus, your contacts are available on your Windows 8.x computer, whether it's your destop or tablet (Surface ideally!).
I would like to know the difference between creating my new contacts in "SIM" vs in "Hotmail". Why creating contacts in "SIM" I have a more limited number of fields to enter my informations. What is the advantage and disadvantage of creating in one vs the other.
Thanks, for the great help. one small question if I enter my contact in Hotmail (in the cloud). Do I have access to all the infos and all the field if I am somewhere with my phone and don't have access to wi-fi internet connection?