The first way to do this is go to the Icon that says contacts and click it. In the top right corner there is a plus button Click that. The next step is to enter their information. (Name, Number, Address, Websites, Email addresses. ect) At the bottom of the screen there is a button for more fields to add. There are some interesting other fields that you can add to someones contact such as: prefix, phonetic spellings, suffixes, notes, and birthdays.
There are other ways of getting contacts to your phone other than just adding them manually.
You can add an address to your contacts from an email you received. Open the email. Click what comes right after the “From:” heading. It will either be the person’s name or their email address itself. This will take you to a screen that will ask you if you want to add it to an existing contact or if you want to create a new contact. Do which ever is appropriate.
If the person who emailed you sends their phone number and any other information, you can copy it from the email before you do the previous step and paste it once you are editing the new or old contact.
You can do the same from an email that you sent. Go to your sent mail folder, open the email and do the same steps as above.
You can enter a new contact from the phone application as well. Go to your recent calls and click the blue arrow on the left. As before you can either create a new contact or add it to an existing contact.