Yes! Once you've chosen a template, and/or are in your Waymark Editor:
Navigate to the Voice Over Panel underneath your video preview
Click Edit to access your control panel
Click the Upload Icon that looks like a cloud to select and upload your pre-recorded voice-over or your own jingle right there.
DIY TIP: Not sure what to say, but want to add a personal touch? Use the AI-generated voice-over script (via the AI Flow) and record it in your own voice using your smartphone. Just be sure to keep your recording a few seconds shorter than your video to ensure it isn't cut off.