'Receipts' in slang means evidence — screenshots, photos, recordings — that proves a claim. 'Do you have the receipts?' = 'do you have proof?'. Often used in arguments about who said what. If your teen demands receipts, they want hard evidence rather than rumours. Useful vocabulary; encourages a healthy 'verify before believing' habit. Originated in 1990s African-American Vernacular English and was popularised by Whitney Houston's famous 'show me the receipts' interview line.