In 451 or 450 Pericles carried a law confining Athenian citizenship to those of Athenian parentage on both sides. No source provides any background to this proposal; it is not even clear whether it was retrospective.
A high school diploma or GED is enough to get started as an office clerk. It is important to have some office skills, such as typing, good phone skills, word processing, etc. Most training is done on the job.
Let's review what steps have to be taken to become a front desk clerk. There are no standard educational requirements for becoming a front desk clerk, but a high school diploma, including coursework in business and computer skills, is beneficial.