If you're interested in downloading the Irisbus Citybus 18m for OMSI 2, here are the general steps:
You can find this bus through both official paid DLCs and free community-made mods: Official Paid Add-on OMSI 2 Add-on Irisbus Family Citybus Pack on Steam includes the 18M along with five other models. Freeware Mods Strefa OMSI Irisbus Citybus 18m Omsi 2 Download
Direct Download — This is the primary 18m articulated model based on Kosak’s original 12m version. If you're interested in downloading the Irisbus Citybus
: Check the readme file included in the download, as some versions require specific font packs or sound mods to function correctly. Steam Workshop::Irisbus Citybus 18m Irisbus Citybus 18m Omsi 2 Download