Office 365 (Web) - How to Create a New Contact
1. Go to People and Contacts. To create a contact, select 
New and select Create contact.
2. This will open a blank contact form. Fill in any details that you want. Select the
icon to see more options for that type of information. For example, if the person you’re adding to your contacts has multiple phone numbers, select the
next to
Phone to add phone numbers.
3. When you’re done, select
Save to save your changes or
Discard to cancel.