To do Alt + H M C on Mac in Excel, download and install Accelerator Keys, then press Option, followed by H, M, C.
Command: Merge & Center
This is how to do Alt + H M C on Mac in Excel with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with Excel.
Alt + H M C combines the selected cells into one larger cell and centers the content. This is commonly used for creating titles that span multiple columns.