This problem can be broken into several components:
Communications channel between the Arduino Uno and the laptop or Android mobile
There are several options. The most common and probably easiest is to do serial communication over USB. The Uno has a USB-serial chip that creates a virtual COM port (VCP) on a computer when you connect the Uno to it via the USB receptacle on the board. This VCP is commonly used to upload sketches to the Uno and also to communicate with the Arduino IDE's Serial Monitor.
Another option for communications between your Uno and the laptop or Android mobile is Bluetooth. You can buy a Bluetooth module for your Uno that will allow this. This may be preferable if you need wireless communication.
Application on the Laptop or Android mobile that interprets communication with the Uno
Now you can communicate between the two devices but you need a program running on the Laptop or Android mobile to actually do something with the communication. This application will receive commands from the Uno, and make the desired interactions with the "cloud server", and perhaps respond to the Uno. You will need to have some sort of a command protocol. The details of this will be dependent on which type of communications channel you chose. There are many ways you can accomplish this and the best option will also depend on whether you will be writing this application yourself or trying to find an existing application that suits your needs.
Arduino Uno firmware
This is a sketch you will write and upload to your Uno that sends commands to the laptop or Android mobile via your chosen communications channel and handles any responses.