Not all Manjaro editions have the needed software installed by default, to install software from this application you need to install
web-installer-url-handler package, that is available in Manjaro repositories.
You are advised to use the installer only if you are on Stable branch, as it might not work on others.
A package is a file that describes how and where software is installed in your OS. Manjaro is not responsible for the contents or quality of the installed software, only install software if you trust it.
Native packages, as the name suggests, are packages that are specifically built for Manjaro. They are officially supported and usually depend on other packages in the system to function properly.
Portable 3rd-party-packages work across distributions unlike traditional native packages.
Flatpaks are self-contained packages with inbuilt dependencies and do not depend on the system to run.
Snaps are self-contained containers that could have dependencies. It's more or less the same as running Ubuntu with a Manjaro Kernel.
Appimages are portable single file package that runs on usespace without the need for being installed.
You should use the default package manager user interface Pamac
(Add/Remove Software). It does support other package formats,
you might need to install libpamac-flatpak-plugin
for compatibility with additional formats and then activate them under Pamac settings.
There is also pamac-cli
and pacman which support native packages.
Other options to manage third-party packages: For Snaps you can install snapd
and for Flatpaks you can install flatpak there is also
manjaro-cli that supports all package formats.