The base map is selected by the administrator from the XYZ layers added to the system.
By default, the publicly available OpenStreetMap layer is used. To improve performance and speed up operation, the OpenStreetMap Cache service has been implemented – tile caching. Images are stored in a cache, which allows faster map display.
The OSM Cache XYZ layer is added to the system by the Client Manager according to the agreements.
Example URL for this service:
https://twojadresgis.pl/osm/{z}/{x}/{y}.png
Important rules:
- Maximum zoom level: 19 (levels above 19 may slow down performance).
- Setting the zoom level above 19 will prevent printing the base map and will increase the time required to generate prints.

- There are also several other base map providers on the market, such as Stamen Maps or Mapbox. Depending on preferences, the administrator can add a custom XYZ base map, which will become the default for the entire application.
- Configuration changes are made in the Administration Panel -> Settings -> General -> Base Map.

The base map is a fundamental element of every Map.

More:
How to add a new base map? (XYZ Format)
OpenStreetMap