There is no centralized Lake Como tourism authority, but each major town and village has its own tourist office, pro loco, or tourism info point.
You'll find the address for them on each town's page on this site, and the links below.
Visitor information for Italy
Tourist information, guidebooks, maps, tips for niche groups (students, LGBT, seniors, disabled, etc.), and more in Italy
“There was nowhere to go but everywhere, so just keep on rolling under the stars.”
— Jack Kerouac