1) What did people use to trim their beards in Prophet Muhammad's time? (SAWS)
2) Is using a trimmer machine allowed? Trimmer also removes all the hair when it is used

1) At the time of rasul, there was no trimmer. They used to trim with scissors.
2) Don’t use zero. Shaving should be such that at least from a distance of 40 steps, one can see the beard hair