Email report, remove header

I have started to work with Piwik for six clients, up to now I find Piwik or better Matomo great.

My question:
How can I remove the black header bar in the email reports?
Or at least the link to the dashboard to right? (see image)

In general the standard reports are fine, but with 6 different websites each owner of a website is NOT supposed to get access to the data of ALL my clients.

Another question, but not so important: How can I remove the URL of Piwik from the report?

Thanks and regards, Dieter.

I found a solution:
If I log in as a restricted user and organize the email report from there, only the allowed websites and reports are visible for that user. So thee is no need to get rid of the headline in the reports.

Stiff it might be nice to get rid of the line with the URL of the piwik server.