Hi @Patti Wolf ,
Welcome to our forum.
When I create a calendar invite or appointment on my iPhone
How did you create the calendar items in your iphone(via default Calendar app, Outlook for ios or others )? In order to further confirm your issue, it's suggested to check these items that created on your iphone in your web mail, if the time zone is also incorrect there, the issue may be related to your iphone itself, please kindly understand here we mainly focus on general issue on Outlook desktop client, we may know little about iphone and iphone apps.
As a troubleshooting method, we could try to switch to other app in your iphone and create a calendar item to check if the new item could display normally on your web mail and outlook for mac, if the new item could work normally, the issue may be related to your app, otherwise, it may be related to your iphone settings. In this case, I have also researched a lot about it for you and found a similar thread(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.), which mentioned some settings in calendar app, please kindly check if it could also work for you. If not, in order to solve it better, it's suggested to post your thread in a dedicated forum and contact dedicated support to get more help.
Hope that would be helpful to you.
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