How do I shorten the length of my field and only allow numeric characters

[Cupcake]

I have a field on a catalog form. The field is requesting the last four digits of the SSN # or Personal ID #. Today the field is setup as a single line text field, but I want to do the following:

a) make the field size = 4

b) I only want to allow that field to have numeric characters

I want to ensure that when I shorten the field size that I am only shortening it for this variable.

Thanks,

Karen

[Cupcake]

Thank you that worked.

Happy Holidays.

[Cupcake]

Thank you this is most helpful. I am going to try this out.