@jodimj I’m using an iPad as I type this. When I scroll to the top of the Mayo Clinic page there are three icons. The first is the bell that shows notifications, the second is the envelope for private messaging and the third is a person that is for your account. If you are still unsure or cannot find the private messaging icon, try clicking on the person icon (very top right of the Mayo Clinic page) and pull down to the Help Center. There will be an explanation of Private Messaging in the Help Center.

I hope this helps.