Alternatively referred to as a cell pointer or selected cell, an active cell is a rectangular box, highlighting the cell in a spreadsheet. It helps identify what cell is being working with and where data will be entered. In the picture below of Microsoft Excel, you can see that the active cell is D8. When a cell is an active cell, it will differ in appearance from other cells such as having a bold border.
You can move the cell pointer by pressing the arrow keys or the Enter key on your keyboard, or you can click on any cell using your computer mouse. By default, the Enter key will move the cell pointer one cell down, but this behavior can be changed by going to Tools and then Options in the Excel menu. Click on the Edit tab and change the Move selection after Enter option, as shown below.