Enabling integration with Mapbox provides autocomplete functionality when a user enters an address (which is particularly useful if you are using the Commerce application) and can display maps when looking at IP addresses and elsewhere. This is an alternative to the preferred googlemaps enhancement, where google maps may not be an option.
In order to create a Mapbox API key, you will first need to create a Mapbox account on their website.
Once logged in, you will see you are automatically given a public token (this is your API Key) for use on your site. Copy this token which will be used in the next step
Now you have your API key, you can add mapbox to your Invision Community site. To do this, visit the following area within your admin CP
System -> Site Features -> Community Enhancements
Once here, select the "Enable" button under Mapbox. You will then be shown the following where you need to enter the key you have just created and select 'Enable'.
Once done, this will enable the integration in various areas of your site where locations and addresses are shown. For example the location shown here in the admin CP on a members profile