Hi Daniel,
As of now, VBA/Macros is not supported in Office Mobile for iPhone.
You may also refer to the following thread which discusses a similar issue and check if it helps.
http://answers.microsoft.com/en-us/office/forum/office_mobile-excel/excel-for-ipad-support-for-vba-and-other-features/4be33af0-46d1-4b7e-8749-57e2228faece
Since we use the App too, we want it to be as awesome as possible. We listen to all feedback and consider it for future releases. Your feedback helps us know which features are most important to you. However, for a variety of reasons we cannot discuss planned
features, their priorities, or the dates that we expect these features to be released.
If you have any other questions related to Office products, get back to us and we’ll be happy to assist you.
Thank you.