Quizlet is one of the most popular educational tools online. You can embed Quizlet wordsets into Moodle using the Poodll Quizlet widget. Embedded in this way, there is no need to edit HTML and the activity will resize nicely to fit the device/screen that the student is using.
First get the URL of the quizlet activity. Do this by copying the URL from the Quizlet activities address bar.
Pop open the Poodll Quizlet widget settings dialog by choosing it from the Poodll widgets dialog.
Paste in the URL that you previously copied, and select the practice activity that you would like to show to the students.
Then the quizlet activity will embed nicely and change size to match the students screen!