Security Groups in Tenant Setting

How does Tenant security groups workf for share to WEB?  Very confused.  I thought someone with Power BI Pro and in Azure AD, would have their email valid for Tenant security group entries.  Also, when trying to locate specific groups, I type in 'C', and see 9 entries starting with 'CAD', I add 'R' and see 5 entries starting with 'CRM', I add 'M and see 7 entries starting with 'CRM', I add space 'U' and see 10 entries starting with 'CRM U'.  This doesn't make much sense.  Can someone help?