Usually this comes from a need to have an apostrophe in a literal constant. E.g., you might have a display field that has text associated with it such as <b>Enter customer’s name . . :</b>. You want the apostrophe to be included in the word “customer’s”.
For me, the simplest method is to create the constant as <b>Enter customer s name . . :</b>; i.e., simply leave a blank space where the apostrophe should go. As soon as that constant is added to the screen format, go back and type your single apostrophe into the blank space.
The constant value should result in being updated to include the apostrophe.