Here are some ways you could use 'can,' 'could,' or 'will/would' to make requests in the given situations:
Your neighbour is playing very loud music and you are preparing for your Science test.
Uncle, could you please lower the volume of your music? I'm trying to study for a Science test.
An old man has parked his car in the middle of the road and it is blocking your way.
Excuse me, sir, could you please move your car? It's blocking the road and I need to get through.
You have just finished your dinner at a restaurant and you have to pay the bill.
Could you please bring me the bill?
Your father has bought a laptop and paid the money. He has to get a receipt.
Dad, will you please ask for a receipt for the laptop you bought?
A lady is standing at the entrance of a chemist shop and you are in a hurry to get in to buy medicines.
Excuse me, ma'am, could I please get by? I'm in a bit of a hurry to buy some medicine.