An input mask is a string of characters that indicates the format of valid input values. It can be used to help ensure that data is entered correctly in a worksheet. An input mask is defined by two parts:
For example, an input mask for a phone number might look like this:
In this example, the parentheses and hyphen are literal characters that appear in the field, and the 9's are prompt characters that appear when you enter data. When you enter a phone number in this field, it must match the format of the input mask exactly. In other words, if you type a space or dash instead of the parentheses or hyphen, Excel will reject your input.
You can use input masks with any data type except for memo fields. To add an input mask to a field, follow these steps:
In the Input Mask Wizard, select Use default mask from each list under Available Masks and then click Next.
Select one of the following options under Edit Mask and then click Next: