I'm looking at my Supplier Onboarding settings and would like to know what the settings for 'Participanr Invite Guidance' are for?

With this setting you can input the URL of a page that could include guidance for hosts when inviting your participants. For example you could specificy which settings they would need to select. on each tab. 

This URL will be present once you click to invite a new participant on the Participant Summary page and will link to the page you specified.