There are no options that are specifically called "Partitioning" and "Addressing" but rather you control their functionality through the available options in the Table Calculation editor.
I'm assuming you're creating the percent to total calculation by adding a quick table calc.
Once you've created the calculation, right click the pill, and click edit table calc. (See screenshot below)
The addressing is on Customer Name and Segment so Tableau is computing the result for each combination of Customer Name and Segment.
At the level controls the partitioning meaning currently, each combination of Customer Name and Segment will show the percent to the overall total.
Please see this article for more information: At the Level – Unlocking the Mystery Part 1: Ordinal Calcs | Drawing with Numbers