Excel's Edit, Fill features can quickly generate rows or columns of cells for you.
While you can use the more formal Edit, Fill menu (below, Figure 1), it is often faster to just fill down or across using Excel's drag and drop feature. Figure 1 - Edit, Fill menu
The keys to using using Excel's drag and drop feature are the drag and drop black square at the lower right corner of each cell and the fill cursor. The drag and drop black square is pictured below in Figure 2. The window is zoomed out to 400% for demonstration purposes only. Figure 2 - Drag & drop square in lower right corner of cell
The animated image below (Figure 3) demonstrates how to do a simple fill down of only one value. To do this, select cell A1, enter the value 1 in cell A1, and press the Enter key. Select cell A1 again, hover over the drag & drop square and the cursor will change to the fill cursor (a solid black crosshair). Left-click mouse down and start dragging to cell A2, A3, ... all the way down to cell A10 and let go of the mouse. Figure 3 - A simple fill down with only one value (plays 3 times). To replay, press F5.
The animated image below (Figure 4) demonstrates a common way to fill down with a series of values such as 1, 2, ... To do this, select cell A1, enter the value 1 in cell A1, and press the Enter key. Enter 2 in cell A2. Select cells A1 & A2 , hover over the drag & drop square and the cursor will change to the fill cursor (a solid black crosshair). Left-click mouse down and start dragging to cell A2, A3, ... all the way down to cell A10 and let go of the mouse. Figure 4 - A fill down with a series starting with 1, 2 (plays 3 times). To replay, press F5.
Below (Figure 5) are series of even numbers, odd numbers, abbreviated days of the week, formal days of the week, abbreviated months of the year, and formal months of the year. One thing to remember is that with days of the week for example, you don't have to stop at the end of the week. You can keep filling down and it will cycle though Saturday, Sunday, Monday, ... Figure 5 - Series examples
All of the demonstrations so far have involved filling down. One can fill up, fill left, but a more common practice would be to Edit, Fill, Right pictured below (Figure 6). Figure 6 - Fill, Right
If you cannot fill down or if you cannot see the drag & drop square (Figure 7 below) then you do not have the right Excel Option checked. Figure 7 - No drag & drop square
To correct this situation, got to Tools, Options, Edit tab and check the "Allow cell drag and drop" checkbox. Then click the Okay button.
The key points to remember when filling cells are to select enough cells before hovering over the drag square and getting the fill cursor. Excel needs the right amount of cells selected before it can guess what series you want.
If you want to do more complicated filling, look into the Edit, Fill menu features of Excel described near the top of this page.