How does the office implicitly say that entry is prohibited during the epidemic?

How can the office implicitly say that entry is prohibited during the epidemic? 1: You can organize a group, pull all company employees who can usually enter the office into the group, and publish group announcements to let everyone pay attention to what everyone should pay attention to during the epidemic and what everyone should do. 2: Prepare relevant notes on paper and communicate them to each other in a visible place in the company.