https://docs.microsoft.com/en-us/office/vba/api/excel.application.onkey#example


Make sure to put this inside "ThisWorkbook" NOT a Module!

Sub Workbook_Open()

  With Application
    .OnKey "{F1}", "Your_Macro_Name"
    .OnKey "{F2}", "Your_Macro_Name"
  End With

End Sub

Sub Workbook_BeforeClose(Cancel As Boolean)

  With Application
    .OnKey "{F1}" 'Clears the setting on close
    .OnKey "{F2}"
  End With

End Sub

Note: F# do have functions so better to use CTRL+SHIFT+{LETTER} Eg: Use this Module to test CTRL+SHIFT+S

Public Sub SetKey() 
Application.OnKey "^+S", "Test" 
End Sub

Public Sub Test()
 MsgBox "Testing"
End Sub



This only works for Microsoft Word (I'd Rec using the above code, but I'm posting for reference)

You must go to File >> Options

Source:

https://wordribbon.tips.net/T008058_Assigning_a_Macro_to_a_Shortcut_Key.html