On each Event, there is a Customer Address, and a Venue Address.
There is an Optional Field for the Venue Name. If you create an Event and enter a Venue Name, it saves other details with that Venue to be recalled again in the future on other Events, such as the venue address details and Venue Notes. Changing the Venue Notes for one Event will change the Venue Notes for EVERY other Event that has the same Venue attached to it.
This settings page is a list of saved Venues so that they can be edited if needed.