Documentation
Versions:
Lizmap 3.8
Lizmap 3.7
Lizmap 3.6
Lizmap 3.5
Lizmap 3.4
Lizmap 3.3
Lizmap 3.2
Lizmap 3.1/3.0/2.x
QGIS allows you to define themes.
You will then find those themes in Lizmap above the layer tree by clicking the button with the same 'eye' icon than QGIS.
You can activate the first map theme on startup. In the Lizmap plugin, go to the Layers tab and click the according checkbox at the bottom of the Project layers part.