Every document in every folder (and every clause in a glossary) is technically ‘optional text.’
• It is ‘optional’ because you can choose it or not choose it when it is presented in the Clause Selection Screen.
Sometimes, however, you don’t want the user to have to select from among every single variation of clause on a specific subject matter. That could end up presenting too many options to the end user, and that can be counter productive. Sometimes (actually, frequently) it is more efficient to provide the user with some text selection options within the source clause. That is what <<*Options*>> and <<*Optional*>> text blocks are all about.
•If, let's say a 'shipping option' is all that distinguishes potentially separate Clauses A, B & C, it may be more efficient to combine the three clauses into one, and provide an <<*Options*>> block which can present the mailing options.
Only actual use, and trial and error, will fully explain the difference between <<*Options*>> text and Clause Selection Screen text, but such trial and error will eventually lead you to the best way of producing documents.
But see the next section for a further discussion and comparison of these practices.