Tourists flow in from countries with good relations and their spending lands in your treasury. Facilities set your capacity (hotels, beaches, museums, theme parks…); if capacity fills you turn tourists away — watch the occupancy bar in the Tourism tab.
Hotels, beaches, museums and theme parks set your capacity. The shortest path is the Tourism tab: build directly with the + button next to a facility family. The same buildings also exist under Economy → Factories & Buildings → Tourism. If the occupancy bar is past 90%, you are turning tourists away — time for a new facility.
Appeal rises with facility count plus health, security, culture and entertainment services. Higher appeal draws richer tourists who spend more; pollution and war scare tourists off.
Exporting games, films and series builds goodwill toward you around the world and raises your appeal to tourists. It is baseline goodwill, not an alliance — and it drains away just as fast if your exports fall or you go to war.
Each facility attracts a different type: casinos draw rich gamblers (but bring crime), museums draw culture tourists, theme parks draw families. Tourist types match the source country's income distribution — casino customers don't come from poor countries.