What is the standard contract size for trading in FX?

Excuse me, could you possibly explain what the standard contract size refers to in the realm of FX trading? I'm interested in understanding the specifics of this term as it seems integral to the overall trading process. Could you elaborate on the significance of this contract size and how it might impact traders in their decisions? Additionally, is this standard contract size uniform across all FX platforms or does it vary depending on specific exchanges or brokers? Thank you for your assistance in clarifying this matter.