If you have calculated a number in the second box, you can copy it to another program. Click Edit and then Copy Result to Clipboard. Open the other program. Most programs have an Edit and then Paste option to paste the number in. You can also paste the value into the first box. Move the mouse where you want to insert the value and hit Edit > Paste Result.
If you have done a Conversion or a Compound Interest calculation, you can copy the result to another program, but the procedure is different. Drag the mouse over the number; it will become highlighted (surrounded by blue). Now Right-click on the mouse and click Copy on the little menu that appears. Open the other program and paste the value in.
Most often you will want to copy the graph.