There are two ways to add a voiceover to Google Slides:

Method 1: Using an external audio recording tool

1. Record your voiceover using an external audio recording tool, such as Audacity or GarageBand.
2. Save your voiceover as an audio file, such as an MP3 or WAV file.
3. Upload the audio file to Google Drive.
4. In Google Slides, open the slide where you want to add the voiceover.
5. Click Insert > Audio.
6. Select the audio file you uploaded to Google Drive.
7. Click Insert.

Method 2: Using a third-party screen recording tool

1. Install a third-party screen recording tool, such as Loom or Camtasia.
2. Open the Google Slides presentation you want to add a voiceover to.
3. Start recording your screen using the screen recording tool.
4. Narrate your slides as you record your screen.
5. Once you have finished recording, stop the recording.
6. Edit the recording to remove any unwanted footage.
7. Export the recording as a video file.
8. In Google Slides, open the slide where you want to add the voiceover.
9. Click Insert > Video.
10. Select the video file you exported from the screen recording tool.
11. Click Insert.

Formatting options

Once you have added a voiceover to your Google Slides presentation, you can format it using the following options:

• Start playback: Choose when the voiceover starts playing. You can choose to have it start automatically when the slide is opened, when you click on the speaker icon, or after a certain number of seconds.
• Loop playback: Choose whether or not the voiceover loops continuously.
• Volume: Adjust the volume of the voiceover.
• Fade in/out: Choose whether or not the voiceover fades in or out at the beginning and end.