Chr(AsciiNumber) will return the character of given ASCII number. Generally this is used when we want to insert single quote(') in our expression or in concatenation, since it is an error to mention single quote between ''.
If we want form a string like this - don't we need to use like below
='don' & Chr(39) & 't'
Or if you want to display Qlikview & Qliksense in two different lines in text object
='Qlikview' & Chr(10) & 'Qliksense' -- Ascii code for Carriage return is 10 --- Chr(10) = Enter key