They must first record a clip of themselves singing, which they must then submit for the casting committee to assess.
Producers also reach out to local musicians across the country and ask them to audition, according to season 1 contestant Vicci Martinez.
Although this regulation has in the past drawn criticism from viewers, duos and trios are still allowed to register and compete.
After passing the virtual casting call, it's not time to sing in front of the A-list gang just yet.
Some singers who don't advance to the blind auditions come back in subsequent seasons for another shot.