Test questions are organized in the Question bank of a course.
Teachers can Export questions and then Import questions into the “Question bank” of another course. The “Moodle XML format” is well suited.
Application examples
Prepare questions and insert them into the test of an exam course
Export questions from an existing test and import as a copy into a new test (and change if necessary)
Pass questions on to interested colleagues
Video
Simply transfer questions to other courses? - Moodle 3.3 - Youtube (in German).