In order to use the Q&A Module, you must first activate it. This can be done within the Solicitation under 'Settings' - 'Other Options'. In 'Other Options' there is a setting to activate the Q&A Module.
Please note that the Q&A Module is defaulted off, so if you would like the default to be on, we recommend templating a solicitation with an activated Q&A Module so it is active on every solicitation created with that template.