Which audio format should be used for editing audio files online

Good morning. My problem is this: about 5 months ago, I've had music composed for some of my songs in a studio that is now closed down on account of Covid. I have used the tracks sent to me and sung out one song in GarageBand. I want to send the vocals to a sound engineer of the studio for editing purposes. As such, I want to know in which format I should export the song from GarageBand...AAC, mp3, aiff etc?

Regards

Dr. Somanna