In addition to his answer, you can. Sudo gdebi package.deb in newer versions of ubuntu, this is not installed by default, so you will need to install it from. After install it says in order to run or execute the program or app,.
If you do this in a tmp dir, the deb file will be cleaned up whenever you empty your tmp folder. These are installed via dpkg, the debian package. I have password safe installed and running ok on my 20.04 lts notebook.
Deb file is actually an archive with control information telling dpkg what to do with those files and other stuff ans zacharee1 has already said. Gdebi will look for all the dependencies of the.deb file, and will install them before attempting to install the.deb file. Otherwise you can manually delete the deb package if you need the disk space. Gdebi gdebi installs a deb package and its dependencies.
It is supposed to be a gui for compiling and packaging.