We have multiple Slack Workspaces: Our main one can be found at knowbility-hq.slack.com. Other companies also have a (or multiple) Slack Workspace.
There are multiple ways to let people take part in Slack conversations in a specific channel.
If people are already in the Slack Workspace you want to invite them to, use the /invite @username command to invite them into the channel. You can also just add them via the details icon and then Add.
For users outside of the Slack Workspace in questions, there are two approaches.
Invite them as a guest to a channel inside our Slack Workspace. (This gives them access to that channel, and other channels they are invited to.)
It is free for us and easy to manage.
Those are specialty channels as they exist in multiple Slack Workspaces at the same time. The use case is for example client projects where it is important that everyone has access in their own Workspace directly.
Instead of two logins for two Workspaces, everyone logs into their own workspace and sees the channel there.
Both Slack Workspaces must be paid accounts to use that feature and Admins from both companies need to acknowledge their creation. All content in the channel is available to both companies.
More information is available on Slack: https://slack.com/features/shared-channels
(Note: For the time being Eric disabled the request of Shared Channels from our Slack instance to avoid the confusion.)
You can still link to channels, for example when you want to use them in email. For that, right click on the channel name either on the top of the channel view or in the sidebar and select “Copy Link”. (Do not go into Additional options and chose “Share this Channel”.)
You can always mention the channel name in Slack, with a # sign in front of it which will then be linked.
Interested members of the Workspace can then preview and join that channel by using that link.