After you have started using Linux for a while you will come to a point in your use that you will want to start installing applications. Each distribution, and even to the level of the Desktop Environment itself, will have different ways of installing applications. If you decide to install Ubuntu, you will use the Software Center; if you decide to use Fedora Workstation default you will use Gnome Software since Fedora Workstation is installed with Gnome Desktop Environment and Gnome has its own software installer; Fedora with KDE Plasma will have Discover for installing software and it would be the same if you installed Kubuntu since that distribution uses KDE as its default Desktop Environment and KDE uses Discover for the software installer. However, even though Pop!_OS is a branch of Ubuntu Pop!_OS has its own Desktop Environment in COSMIC hence the difference in a software installer via their Pop!_Shop. Its all a little bit confusing, and some would even accuse it of being fragmented. But in all cases you will find that installing software through those tools are a breeze and easy to use for installing all types of software.
If you get to a point in your use of Linux to be an advance user you may find it easier to just install software via command line interface in the terminal emulator. If you use a Red Hat based distribution you will use yum or dnf (yum is being deprecated to be replaced with dnf) to install software; in a Debian based distributions you will use apt; in an Arch base you will use yaourt or pacman. However two newer forms of software installers in snap (Snapcraft – snap repository) and flatpak (Flathub – flatpak repository) have come along to be the more popular use of installing software and in some cases the GUI software center in a distribution will use the flatpak repository to install applications for you. And finally another popular alternative of installing applications is via an AppImage. One thing to note with an AppImage, even though I have it listed under command line installation in my presentation, a majority of the time you can just double-click on the file in your file manager within a Desktop Environment and it will launch automatically for you. A caveat of an AppImage, however, is that you have to make sure the file is executable first before double-clicking to install; I believe this to be a security feature.
Another thing to note in regards to command line using yum, dnf and apt is that those commands can also be used to update operating system and security updates. However, most GUI software centers in the distros and Desktop Environments will inform you of OS and security updates and allow for updating through that interface also.