With Record Type
If a Record Type has been defined for the record you are viewing then you will most likely see a data entry screen similar to this one.
This screen has fields and a Save button because this record has a Record Type defined. If you have data entry rights than you can change the data values and click Save to update the record. If you do not have data entry rights then you will see this view in read-only mode.
If you are the administrator you can define record types in the Admin section under Record Types.