There are two ways you can edit attribute values in ArcMap. You can open the table and edit in the Table window, or you can open the Attributes dialog box. As with editing map features in ArcMap, editing the attributes of features and values in tables takes place within an edit session. When you've completed your edits, you can save them and end the edit session.
- Click the Editor menu on the Editor toolbar and click Start Editing.
- Right-click the table or layer in the table of contents and choose Open Attribute Table.
- Click the cell containing the attribute value you want to change.
- Type the values and press ENTER.
The table is updated.