You can close the current document only or close Serna window with all opened documents.
in the top right corner of the
main menu.
in the top right corner of Serna window.If you try to close a document that has been modified but not saved, you will be asked what to do:

To save the changes and close the document, click Yes.
To close the document without saving the changes, click No.
To cancel the closure of the document, click Cancel.