The invitation to bid gives the date, the place and whether the meeting is mandatory. Miss a mandatory meeting and the owner can reject your bid.
Many meetings include a site walk. A demolition sub sees the real ceiling height. A flooring sub sees the condition of the existing slab.
Read the packet before you go. Bring your questions in writing. Answers given out loud do not change the contract. Only an addendum does that.
Sign the attendance sheet. Then watch for the addendum that records the questions and the answers.