Share mints a link to the call and opens it in a small window with the address, Copy and Revoke. It is there in the antechamber before you join, and in the conference bar afterwards, so you can invite people and then walk in. Closing the window leaves the button reading Share link, which opens it again. Pasting the address into a channel or a private message draws a card instead of a bare address — any such link becomes a card, including one somebody sent you from outside.
What a link does not do
A link says which room it is; it never says you may be in it. Whoever follows it still has to be registered with NickServ and a member of the channel, and a locked conference still refuses everyone but its moderators. Only a registered nickname can mint one, because the link records who made it.
See also: Channel Conference · Conference in Its Own Tab
