Started from a fork of Koplin, Xilinota maintains to be compatible with Joplin in most aspects. The simplest way to import from Joplin on the desktop is to copy or rename the two config directories of Joplin. The two directories generally are Joplin and Joplin-desktop under "${HOME}/.config". Consult Joplin related materials for details. Otherwise, you can import the JEX file exported from Joplin.
Xilinota can import complete Evernote notebooks, as well as notes, tags, images, attached files and note metadata (such as author, geo-location, etc.) via ENEX files.
To import Evernote data, first export your Evernote notebooks to ENEX files as described here. Then, on desktop, do the following: Open File > Import > ENEX and select your file. The notes will be imported into a new separate notebook. If needed they can then be moved to a different notebook, or the notebook can be renamed, etc. Read more about Evernote import.
Xilinota can also import notes from many other apps as well as from Markdown or text files.
Xilinota can export to the JEX format (Joplin Export file), which is an archive that can contain multiple notes, notebooks, etc. This is a format mostly designed for backup purposes. You may also export to other formats such as plain Markdown files, to JSON or to PDF.