Can I open multiple files and amplify all of them at once?

I’m using Audacity 2.4.2 with Windows 10. I download podcasts as MP3 files to my phone and listen to them through my car’s radio using an auxiliary cable. Even with my phone’s volume turned all the way up and the car radio turned all the way up, they are not loud enough to hear over the road noise. The workaround I have discovered is to open up each MP3 file in Audacity, then use the effect>amplify feature and save the amplified file to my phone. This increases the volume so that I can hear the podcast.

But this process is tedious for a series that is several episodes. Is there some way to open several MP3 files, use the effect>amplify feature on all of them at once or consecutively, and save all amplified files?

You could create a Macro containing the Normalize effect followed by one of the Export commands (such as “Export as MP3”), then use the Macro to batch process your files (see: