This function is used mainly to get rid of empty paragraphs in a document.
will insert the value of the AddressLine3 data element only if that data element has a non-empty value. If the value IS empty, then the entire paragraph containing the field is removed.
Note that this behaviour applies even when there is other text in the paragraph, and so the function should be used bearing that in mind.
Before this function was introduced, the only other way to achieve the same result would have been to code the following:
<<If(AddressLine3 != '')>>