Hi gadarsh,
First, my pleasure to assist you.
As per your description, please don’t worry, we can work together to narrow down and resolve the situation.
As you mentioned, “Is anyone else's powerpoint format changing on emailing” may I know does it mean PowerPoint formatting change when you email to others on the M1 MacBook?
If my understanding is right, for the situation you encountered, we do understand the inconvenience caused and apologize for it.
First: are the fonts used by the presentation installed on both machine? When we use a font in a presentation or Word document, then open that file on a machine that doesn't have the font, it will open but will look very different.
If you save your presentation as a (.pdf) file, and then attach the PDF file to an email message does it make any difference.
Meanwhile, to narrow down your issue, please tell us more information below to let us help you:
1. Please confirm if the issue only happens in the specific PowerPoint file? Or all files.
2. Confirm whether other applications also get the same problem (formatting changing on emailing)? Such as Word and etc.
3. The version of Mac OS and Office
Find out which macOS your Mac is using
About Office: What version of Office am I using?
Your understanding and patience will be highly appreciated. I hope that you are keeping safe and well!
Best regards
Waqas Muhammad