The sheet into which you'll be entering the values you intend to have colour coded.

Assume that is Sheet1... in native XL right click on the tab Sheet1 and select View Code - paste the code provided into the resulting window.

Once in place this means that whenever you enter value(s) into Column A (adjust code to suit) the values will be colour coded on a character by character basis as and where they meet your criteria.

NOTE:
per my point on your other post regards UpperCase conversion ... if that forms part of this exercise you will need to merge the two Change routines as a given sheet object (eg Sheet1) can have only one Change event.