Yes, you can add typing instructions to an Excel cell using the Data Validation feature. Here's how:

1. Select the cell where you want to add the typing instructions.
2. Go to the Data tab in the ribbon and click on Data Validation.
3. In the Data Validation dialog box, select the Settings tab.
4. In the Allow dropdown menu, select "Custom".
5. In the Formula bar, type the following formula:
   Code:

   ="Type last name, press TAB"

6. Click on the Input Message tab.
7. Check the "Show input message when cell is selected" box.
8. Enter a title for the input message (e.g. "Instructions").
9. Enter a message to display (e.g. "Type last name, press TAB").
10. Click OK.

Now, when you select the cell, the input message will appear as a tooltip. When you start typing in the cell, the message will disappear. If you want to edit or remove the instructions, simply select the cell and go back to the Data Validation dialog box.