"Contract cheating is when a third party produces or completes academic work for a student, and the student then presents the work as their own. The student might have personal connections to the third party, or the student might pay a fee and outsource the academic work to the third party" (1).
Eaton, Sarah Elaine, et al. “Interinstitutional Perspectives on Contract Cheating: A Qualitative Narrative Exploration from Canada.” International Journal for Educational Integrity, vol. 15, no. 1, Dec. 2019, pp. 1-17.
"Contract cheating occurs when a student procures a third party (who knows about and benefits from the transaction) to produce academic work (that is usually, but not always assessable work) that the student then submits to an educational institution as if it were their own. It constitutes a form of plagiarism: presenting someone else’s words and/or ideas as your own without appropriate attribution. The contract can be either paid or unpaid; paid work obviously involves payment in money, but unpaid work could involve favours and other forms of mutual obligation" (1).
Ellis, Cath, et al. “The Infernal Business of Contract Cheating: Understanding the Business Processes and Models of Academic Custom Writing Sites.” International Journal for Educational Integrity, vol. 14, no. 1, Jan. 2018, pp. 1-21.