Apps
There are well over 100,000 applications available for your Linux system, every kind of app for science, education, creativity, office, or fun free for the asking. One of the dangers of Linux lies in getting over-excited about this vast selection and over-installing, resulting in bloat, which can slow down your system. The Linux built for you was intended to be lean and mean, minimalistic and powerful. Check out the links above to learn what was installed for you. Learn how to install more, but research well to be sure you are installing what you really want and so keep your system high functioning.
To discover new apps, use your favorite search engine. Enter a search term like "biology apps for Linux" or "photo editing apps for Linux" and research the results to see what might work for you. Then you will have to see if the app is available for Arch, your Linux distro. To do this, open the terminal and type "pacman -Ss appname" without the quote marks, where appname is the name of the app you are looking for. If it is available, you can type "sudo pacman -S appname" to install it. Follow any prompts, usually just a "y" for "yes" if using English, when asked if you want to install it. Look and see if there are any other packages called dependencies that need to be installed. If there are too many of these you may want to think twice about whether this app is something you really need.
Another way to find and install apps is to search for flatpaks at Flathub. These are apps created to be universally compatible and distro independent. If you find an app there, install it according to their directions for Arch Linux. It is recommended that you first search using "pacman -Ss" from the terminal first. On your computer at the moment, Zoom, Wire, and Signal are all flatpak apps, since there are no versions of these apps officially packaged and maintained for Arch Linux.
The day may come when you no longer need an app and want to remove it. This is a good idea to keep your computer free of clutter. To remove an app, just go to the terminal and type "sudo pacman -R appname" and follow prompts. After this it is recommented to type a new command, "cleanup" to remove any orphaned packages. This helps keep your system mean and lean, and trouble-free. Enter password if prompted. As usual with the Terminal, you will see no dots or other signs of what you are entering. If you don't get your password right you'll be asked to re-type.