sudo apt install deb name code example
Example 1: how to install .deb file ubuntu
sudo dpkg -i package_file.deb
Example 2: install ubuntu deb
#install downloaded .deb
sudo dpkg -i /path/name.deb
#install packages
sudo apt install package_name
sudo dpkg -i package_file.deb
#install downloaded .deb
sudo dpkg -i /path/name.deb
#install packages
sudo apt install package_name