1. According to Baidu Encyclopedia information query, audio can be inserted into a PDF document with the help of Zhou Jin PDF editor. First, open a PDF editor and choose to create or open a PDF file.

2. Secondly, at the top of the interface, select the sound tool.

3. Then click the mouse in the blank space of the document and click "Browse" in the pop-up window to insert the audio file.

4. Then, when the button lights up, the addition is successful. Click "OK".

5. After saving, double-click this icon to play the audio file.