I read different articles on how to configure Hybrid Search, Delve etc. in SharePoint and came to know that you need to have a domain for SharePoint Hybrid to work.
As far as I understand a domain is needed because on-premise SharePoint cannot be accessed from outside from Office 365 so we will need to buy a domain and map it to on-premise SharePoint server so for e.g. it will become
But I get the impression from articles that domain is needed at Office 365 end and this is where it will be configured so I am confused about why it is needed? Why my tenant for e.g.
https://mytenant.sharepoint.com won't work in Hybrid.
Another question, if I am just configuring Cloud Hybrid Search, even then I need a domain to be configured in Office 365?