Primarily, this function compares two text strings to see if they are an exact match. Text strings even have to match in the case formatting (lower or upper) for each character. Wild as it may sound, you can also compare container fields to see if the contents are exactly the same. If the two things being compared are an exact match, you will get a TRUE result. One very common use for the exact function is in the various areas of data validation/verification needs.
Going back to using the exact match on container fields, the exact function even compares if the container files information is stored within the field or just a reference to where the data actually resides.
Exact( “FileMaker”, “FileMaker”) = True
Exact( “FileMaker”, “FILEMAKER”) = False