Go to the destination module (module to which you want to import questions).
Select More from the contextual navigation menu.
Select Question bank.
From the Questions drop-down menu on the top left of the page, select Import.
In Moodle 3.9, Question bank is available from the Settings menu on the right of the page.
Select file format
Select Moodle XML format.
Upload file
Either drag and drop the file into the Import area or select Choose a file to Browse to the correct location on your computer, choose the file to import and select Upload this file.
Import file
Select Import.
Continue import
You will receive a message about the number of questions being imported and any errors being recorded. Select Continue at the bottom of the page.
The questions will then be available in your Question bank and can be added to your Quiz activity.
Check your questions have imported correctly before using them, especially any with images attached as occasionally images do not import correctly.