To find the first non-digit in a text value in Excel, you can use the following formula:

=FIND(CHAR(1),SUBSTITUTE(A1,{"0","1","2","3","4","5","6","7","8","9"},CHAR(1),LEN(A1)))

This formula will return the position of the first non-digit character in a text string. For example, if the text string is "123abc", the formula will return 4, since that is the position of the first non-digit character ("a").

You can also use this formula to find the position of the first non-letter character in a text string. For example, if the text string is "abc123", the formula will return 4, since that is the position of the first non-letter character ("1").