sudo apt install <deb name> code example

Example 1: how to install .deb file ubuntu

sudo dpkg -i package_file.deb

Example 2: install .deb files in terminal linux

sudo dpkg -i /path/to/deb/file
sudo apt-get install -f

Example 3: install deb file in ubuntu

sudo apt install path_to_deb_file

Example 4: install *.deb file in ubuntu

Install a downloaded program in Ubuntu - Linux
sudo dpkg -i package_file.deb
//or
sudo apt install path_to_deb_file