Microsoft Excel files are organized into a set of worksheets, each containing its own set of data. By default, a file has three worksheets, but you can merge the worksheets from one XLS file into another. The process is completed using the worksheet tabs at the bottom of the XLS file.

Start Microsoft Excel and open the existing sheet into which you want to merge information (call it file1.xls) from another file. Open the other file (file2.xls) from which you want to merge information. Both files must be open at the same time.

Right-click the first tab at the bottom of file2.xls (which contains the information you want to merge into file1.xls). Select "Move or Copy..." from the list of options. The program loads a new dialog box.

Choose the name of the other file (file1.xls in this example) from the "Move Selected Sheets to Book" drop-down box.

Click "(move to end)" from the "Before Sheet" box. Click "OK" to merge the worksheet from file2.xls to file1.xls.

Select the next worksheet in the open file2.xls document. Repeat this process (steps two to four) to merge all worksheets into the first file (file1.xls).