One way to do this is to use a full column reference.
You will see Excel choose the entire column.
As entries are added to the table, the formula will automatically include the new amounts.
Advantages and risks
The main advantage to full column references is simplicity.
However, full column references come with certain risks.
One risk is that you may accidentally include extra data in a calculation.
Another risk is performance.
Alternatives
There are good alternatives to full column references.
Another option is to use adynamic named range.
These values can be numbers, cell references, ranges, arrays, and constants, in any combination.
SUM can handle up to 255 individual arguments.
