To make data entry easier in Excel, you can create a drop-down list. When you create a drop-down list for a cell, it displays an arrow in that cell. To enter information in that cell, click the arrow, and select option that you want. To create a drop-down list from a range of cells, use the Data Validation command in the Data Tools group on the Data tab.
Steps are given below
Step 1: Open your excel sheet. Select excel sheet where you define drop down list e.g. If your main sheet is 1 then open sheet 2. On this page insert drop down list item as below image.
Step 2: Now, go to your main page and select cell where you put dropdown. If you put single dropdown then select single cell. For multiple dropdown select multiple cells as below image. First select cells then click on Data Validation option.
Step 3: When you select Data Validation option, one popup window will be appeared as below image. In opened window select list option then click within Source textbox.
Step 4: After selecting Source textbox, go to excel sheet 2 and select list item as below image. After selecting list item press ok button for comeback your main page.
Step 5: Check dropdown menu on your main page as below image.