What is the difference between presale and normal tickets?

Could you please elaborate on the distinction between presale tickets and regular tickets? I'm curious to understand how they differ in terms of availability, pricing, and any additional benefits or restrictions that may apply. I've noticed that some events offer presale options, but I'm not quite sure what the advantages are compared to buying tickets at the regular time. Could you also explain if there are any specific conditions or requirements that need to be met in order to purchase presale tickets? Thank you for your assistance in clarifying this matter.