Final answer:
Slack channels can be created at any time by users with the necessary permissions.
Step-by-step explanation:
The creation of a Slack channel is not limited to a specific day. It can be created at any time by a user with the necessary permissions. Slack is a collaboration platform that allows team members to communicate and share information in real-time. Channels within Slack can be created for specific topics, projects, or teams, and can be joined by invited members.