Excel already has many numeric and date formats built into its Format Cells dialog box. But, you can create any format you need, including custom formats for,
To create a custom numeric or date format,
1. Select the cell where you want to use the custom format. Once you create it you can use it anywhere in the workbook.
2. Right-click and choose Format Cells.
3. Select the Number tab.
4. Select Custom in the Category list.
5. Look through the list to see if there is a pre-defined custom format similar to what you need. If so, select it.
6. In the Type text box, edit the numeric or date pattern to create the custom format you need.