Watch the video below to have an idea of how external users can collaborate with your employees in Bitrix24:
Intranet and Extranet users have different access levels to your Bitrix24. Extranet users are able to participate in extranet workgroup discussions, share files, create tasks, post messages and perform other collaborative activities inside that extranet group. Outside the extranet workgroup extranet users also have access to Company’s employees list and contacts. Here is what external user will see after accepting an invitation to your intranet (sent from extranet workgroup):
See Extranet vs Intranet user comparison chart.