Some resorts have only 1 lift pass option available, which means you'll be able to use all the available lifts in the resort. These are generally for resorts that are not linked to others or only have 1 advertised ski area. Whilst some other resorts are connected and require an upgraded lift pass in order to use a linked resort or other area.
Signs will be in place warning you if you are about to go out of area so please pay attention to them as you'll need to pay to come back on the lift or use public transport around the mountain if you get stuck on the wrong side.
You can check which type of pass you have by checking your booking and seeing if there is an upgraded pass option. If this doesn't appear, you have only 1 lift pass type. If this does appear, the selection will let you know which type of lift pass you have