Ansible works by connecting to your nodes and pushing out a small program called Ansible modules to them. Then Ansible executed these modules and removed them after finished. The library of modules can reside on any machine, and there are no daemons, servers, or databases required.
In the above image, the Management Node is the controlling node that controls the entire execution of the playbook. The inventory file provides the list of hosts where the Ansible modules need to be run. The Management Node makes an SSH connection and executes the small modules on the host's machine and install the software.
Ansible removes the modules once those are installed so expertly. It connects to the host machine executes the instructions, and if it is successfully installed, then remove that code in which one was copied on the host machine.