A database is only as good as the information it contains. Over time, you'll need to edit the information in your database to keep it accurate and up-to-date. ArcMap lets you edit the attributes of features displayed on your map and also the attributes contained in tables that are not represented geographically on the map (for example, a table of monthly sales figures).
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.
Editing values in the table window
Once you begin an edit session, you'll notice a pencil icon next to the Table Options button 
on the Table window, indicating that the table can be edited. In addition, those fields that you can edit will have a white background in the field heading. You can make any of the attribute changes you need by clicking a cell and typing a new attribute value.
Editing attributes through the table window allows you to quickly make changes to several features (records) at once. You can edit any of the values that appear in a table as well as add and delete records. You can also use the field calculator to change the values of a particular field for several records at once.
If you have a list of values, you can copy and can paste them into the table to populate successive cells. For example, you can take a list from a text editor or Microsoft Excel, copy the values, then right-click a cell in the ArcMap table window and click Paste. When you paste, make sure you are not in cell insert mode (in order words, that the cursor is not flashing in a cell), so the values will go into multiple cells, not just a single cell.
You can increase your productivity when working with the table window by using keyboard and mouse shortcuts. For example, if you want to work methodically through an entire table row by row when you are editing or reviewing data, press CTRL+ENTER.
Learn about keyboard shortcuts for working with tables
Copying and pasting records in multiple cells
It is easy to paste data into vertical consecutive cells in a column when you are populating a table. This can save time if you are updating an existing table and want to use information in other applications, such as Excel and Word. For example, you may want to use Excel to assemble and spell-check updates to an existing field in an ArcMap table and simply paste the values from Excel into the table instead of loading the Excel table into ArcMap and joining it to your table.
In this example, four consecutive cell values in a column in an Excel spreadsheet will be pasted into four consecutive cells in a field in an ArcMap table. First, select the cells in Excel as a block and copy the block to the clipboard:
In ArcMap, right-click the first cell at the top of the vertical block of consecutive cells and click Paste. The values are pasted into the field in the same order they occurred in the Excel file:
To increase the size of the rows so the text wraps inside the cell, click Table Options , click Appearance, then increase the Cell Height value.
Editing values in the Attributes window
When you're editing the attributes of specific map features, you may find it more convenient to use the Attributes window 
, accessed from the Editor toolbar. This dialog box is tailored to updating the attributes of specific map features. To populate the Attributes window, you need to select at least one feature.
