I have this arduino motor shield, and I want to connect a Bluetooth module, but don't know how (the tx and rx pins are used by the plate). Tried to sold it but now I don't have the tin to do it. So I want to know if I can use this holes (don't know their names) "the ones encircled in red" to connect the Bluetooth module. Thank you folks.
You are looking at the wrong place. Tx and Rx are at the bottom of you picture (new picture at the bottom to help you). What you need to do is to get a jumper, heat up the Rx pin and put the jumper in the molten solder. That is not the ideal choice but because you don't have enough solder, thats the way to go. To the same to the Tx pin, GND, and VCC.
A more permanent and clean way of doing this will require extra solder (which you dont have at the moment) and some "shield headers" (aka stackable headers). This will let you connect the shield to your Arduino while still leaving you with all of your female headers.