I'm going out of my mind trying to resolve this issue. I have succeeded at creating and using macros without issue, yet all my efforts at testing a simple VBA form command button based on  youtube instructions fall flat. I have spent several days researching every possible cause and solution without success. I have even gone as far as removing and reinstalling Microsoft 365, as well as factory resetting Excel by deleting Excel's folder using RegEdit. My non-form macros work without issue. Yet creating a single form command button to general a VBA MsgBox fails to work. Please keep in mind that I usually have no difficulties resolving any problems that come my way. This time however, NOTHING!. NADA! 

I'm going out of my mind trying to resolve this issue. I have succeeded at creating and using macros without issue, yet all my efforts at testing a simple VBA form command button based on  youtube instructions fall flat. I have spent several days researching every possible cause and solution without success. I have even gone as far as removing and reinstalling Microsoft 365, as well as factory resetting Excel by deleting Excel's folder using RegEdit. My non-form macros work without issue. Yet creating a single form command button to general a VBA MsgBox fails to work. Please keep in mind that I usually have no difficulties resolving any problems that come my way. This time however, NOTHING!. NADA! 

Sleppy52 

\"creating a single form command button to general [generate?] a VBA MsgBox fails to work.\"

That's a bit vague. Are you attempting to create a form (UserForm) that the user will interact with, which will contain this command button? Or are you attempting to place a (form) command button on a worksheet? (Or possibly both.)

In the former case, your MsgBox statement will go into the Click event handler for the button you create. That event handler will be part of the code module for the form. (What user action do you intend to occur to cause the form to be displayed? The click of a button on a worksheet? A particular change to a particular cell value? Some other user action?)

In the latter case, your MsgBox statement will go into a macro for the button you create. That macro is part of a standard code module (which Microsoft ambiguously calls just a module, but there can exist: standard code modules not associated with any particular worksheet, worksheet code modules, workbook code modules, userform modules, class modules…). (Excel would have prompted you for the name of the macro as soon as you created the button.)

Here's how the Project Explorer window (a child of the VB Editor window) might appear.  (Solver is an add-in that you might not be using; it is not required for this problem.)

Edit: Oh, and are you using Excel for Windows, or Excel for Mac?