Convert Letters to lower case in InfoPath

Step one:

Open infopath create the field required to convert to small letters.In our case I am using a field1

Step two:

·         Write an Action rule for the field1 with no Condition. 

      ·         And add an action to “Set a fields value” 

      ·         A Rule Details box opens.

      ·         In this Rule details box select field1 in the Field Selection

      ·         For Value box Click fx and enter this formula

translate(field1, "ABCDEFGHIJKLMNOPQRSTUVWYXZ", "abcdefghijklmnopqrstuvwyxz")

Step 3:

Now you can see the entered capital case letters will be converted to small letters.