Hi @Jan Pěček
Thanks for reaching out!
As per my research and testing, I am able to send the meeting invitation with custom body (logo, footer etc.) using graph API- POST https://graph.microsoft.com/v1.0/me/events
and I am receiving the invitation with customized body. However, I noticed that it is taking some time/delay to reflect changes into the system.
Below are the screenshots for your reference.
Hope this helps.
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