Is there also a general link so that prospect community member can be invited to our community? Of course I can do this also via the Admin panel and Invite members but would like to use other invite means as well!

Hi David. We do not have an "Invite Link" at this stage. We have the "Registration by admin's approval" on our roadmap though. 

However, if the community registration is "Public", you can simply share the URL of the community:

• If the "Access" is private, one the user opens the community URL in a new tab, the system shows the sign-up/log-in page and asks the user to login to access the community.
• If the "Access" is public, the user can brows the community and if the user wants to do any activity, the system will ask to sign-up.

If the community registration is "Invitation Only", the only way to register to the community is by receiving an invitation email from the admin. In this case, sharing an invite link does not make sense, as anyone can use the same link to register and the link can be used to create many spam accounts. 

If the community registration is by "SSO", therefore, only the users going through the SSO process are able to register into the community, which is the whole point of the SSO app. Although, you can enable SSO but still keep the public registration open as well.