There are some document templates here: https://cgit.freedesktop.org/libreoffice/core/log/extras/source/shellnew
They ony get used on Windows. For Linux, we need to install them to /usr/share/templates/ and create some .desktop files in the same directory that look like this:
Comment=Enter LibreOffice Writer filename:
Here’s a discussion about the topic: https://forum.manjaro.org/t/kde-edition-dolphin-create-new-menu-comes-pre-populated-with-libre-office-templates/69261
Steps to Reproduce:
“right click → Create new ...” into a folder window in Dolphin
The menu doesn’t contain LibreOffice entries.
The menu should contain one entry for each LibreOffice document type.
User Profile Reset: No
This is the job of Linux packagers. Like is said in the forum topic "It would be great if these files were included by default in the manjaro libre office package". Manjaro can do it, if they want.