I am assuming you're referring to adding a contact in the Contacts app.
To enter information in your contacts, do the following:
1. Initiate the Contacts app
2.Tap on the + sign in the upper right corner
3 .Fill in the information
4. Tap "Done" in the upper right corner.
5. Tap "All Contacts" in the upper left corner
6. Look to see if the contacts you just added is listed.
7. Just in case, and if displayed, tap on "Groups" and then tap on "All Contacts" to place a checkmark next to it.
8. Select "Done" in the upper right corner and then re-check for the new contact.