Most non-NA locations will hold the total rental plus taxes. Some will also tack on the LDW margin should you decline it.

In some countries, mostly eastern Europe, Africa and some Asian, they'll make you sign a paper charge slip that includes all those costs but will give it back when the car is returned. Usually they do not put a hold on or process that slip.

There are some conventions for this, but you need to allow plenty of "open-to-buy" margin because there is less consistency than you'd like.

BTW, one way rentals, especially multi-country ones, are a completely different issue.