The world’s P2P (person-to-person) remittance market is estimated to be over the US$ 600 Billion
Source:
https://www.knomad.org/data/remittances
You can also watch this video for a brief explanation
Source:
https://www.knomad.org/data/remittances
How big is the international money transfers market?
Source:
https://www.knomad.org/data/remittances