Using MS 365

I have a table with three blank cells in one column. I want to be able to type in a currency amount in both blank cells (or have it formatted to currency) and then have Word SUM the currency amount in the other blank cell. From my research, there has to be a value in the cells and then you can add the formula =SUM(ABOVE) or just click the AutoSum button.

Is there a way to:
Format all cells to currency.
Type in a formula to SUM the cells once values are added.

Thank you in advance for your help.
Karen