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Your code couldn't run because it is in another file, apparently one you downloaded. In the attached workbook the two buttons are now working with code which is located in the same workbook. They do what you want.
You will find it in the code module 'DataInput' as well in the code sheet of the worksheet 'Sheet1 (AddExpense)'. Please read the comments I added to this code so that you understand the functionality I added. Simply said, I removed the existing formula-based automation of date entry and total calculation (except in the grand total) and replaced it with VBA based automation. To limit this automation I inserted a named range "Invoice" (A3:N20). I removed the existing 'Table2' in the Source Data sheet because it interfered with the copying process.
Note that the cell formats will be copied from the 'Add Expense' sheet along with the data. Good luck!