How does WeChat voice switch between handset and hands-free?

In terms of mobile phone model "OPPO-Reno5-Pro" and mobile phone "WeChat version 8.0.33",

Press and hold the voice message, and then click the handset to play or click the speaker to play.

1. Open the mobile phone WeChat and enter a chat box.

2. In the chat box, press and hold the voice message, and then click the handset to play.

3. Similarly, press and hold the voice message and click the speaker to play.

This is how the mobile phone WeChat voice message switches between the receiver and the speaker.