SSH is installed but not enabled by default in Raspberry Pi OS. It could easily be enabled using raspi-config utility.
Steps to enable SSH server on Raspberry Pi (Raspberry Pi OS):
- Open Raspberry Pi Software Configuration Tool (raspi-config) from the terminal.
sudo raspi-config
- Select Interfacing Options from the main interface.

- Choose P2 SSH in the Interfacing Options menu

- Select Yes to enable SSH.

- SSH server is now enabled.
