Please note that the customization features are exclusive to the Agency Edition. Learn more
here.
Yes, you can share unlimited custom-branded reports with your client members.
Go to Reports. Create a custom report with a report title and save the report.
Click
More from the top right corner of the screen and select
Share this report with Client Members.
You can share the report with all of your client members invited to your brand by clicking
Select all or you can select a few client members and share with them.
Only when you share a report will it be seen in the client's portal.

You can export it as a PDF or PNG file and also email the report to your clients. The below image is an example of a custom-branded report.