saving a slowed-down audio file (mp3)

Macos10.4.5
Audacity 2.3.2

Hello. I’m studying a language and am using audacity to ‘slow down’ audio files from language podcasts to get a better sense of pronunciation. How does one save the file so you can play the ‘slowed’ version at a later date and perhaps on another computer? Thanks in advance for any answers.

Export the project to a WAV, AIF or MP3.
– Bill