We have added a pause SSML tag, so that you can add silence or a blank duration, which helps in adding some music or a simple pause.
Step 1 : Place your cursor at the position, where you wish to add the pause.
Step 2 : In the menu bar click on the 'pause' dropdown and select the pause duration and click on submit.
Step 3 : Select your favorite voice and click on 'Convert to Speech' button
Here is the final Audio result.