PROPER function for dynamic data entry?

Fellow Forum Members,
How do I apply the PROPER function to an entire column while the PROPER formula itself resides in a single cell? In this case my formula looks like this, "=PROPER(A:A)" in cell C1. My goal is for Column A to automatically format the data I input in this format:

Column A1
Thomas
Smith
Baker

However, this is what I get:

Column A1
thomas
smith
baker


What modification do I need to make to "=PROPER(A:A)" so that Column A dynamically modifies the data with an UPPERCASE letter for the first letter of a word as I type it in? My goal is not to create a second column of data that applies the PROPER formula by filling it down and referencing to a first column. I can't have duplicate columns of data. Any help will be greatly appreciated. Thanks in advance.