Layering is the second stage of the money laundering process, in which the launderer moves the funds around to create distance and confusion between the source and the destination of the illicit proceeds. Layering often involves multiple transactions, such as wire transfers, shell companies, trusts, and offshore accounts, that make it difficult to trace the origin and ownership of the funds. Layering is intended to disguise the audit trail and provide anonymity for the launderer12.
Placement is the first stage of the money laundering process, in which the launderer introduces the illicit proceeds into the financial system, often by breaking them into smaller amounts or using cash-intensive businesses12.
Structuring is a technique used in the placement stage, in which the launderer deposits or withdraws cash in amounts below the reporting threshold to avoid detection or suspicion12.
Integration is the third and final stage of the money laundering process, in which the launderer reintroduces the funds into the legitimate economy, often by purchasing assets, investing in businesses, or mixing them with legal income12.
References: 1: ACAMS (2020), Study Guide for the Certification Examination, 6th Edition, ACAMS, Miami, FL, USA, www.acams.org/en/cams-certification-package-6th-edition, pp. 12-14. 2: ACAMS (2020), CAMS Examination Preparation Video, 6th Edition, ACAMS, Miami, FL, USA, www.acams.org/en/cams-certification-package-6th-edition, Module 1.

Accountants can be involved in money laundering schemes in various ways, either knowingly or unknowingly.
Some of the common methods that accountants can use to launder money are:
Overstating income to hide excess cash: This method involves inflating the revenues or profits of a business to conceal the origin of illicit funds. For example, an accountant can create fake invoices or receipts to justify the deposit of cash from illegal sources into the business account. This can make the cash appear as legitimate income from the business operations.
Acting as a conduit for transferring cash between accounts: This method involves using the accountant's own account or a third-party account to move funds around and obscure the audit trail. For example, an accountant can receive cash from a client and deposit it into their own account, then transfer it to another account or withdraw it in a different location. This can make it difficult to trace the source and destination of the funds.
Acting as a designee for someone who wishes to hide their identity: This method involves using the accountant's name or credentials to open accounts or conduct transactions on behalf of a client who wants to remain anonymous. For example, an accountant can act as a nominee director or shareholder for a shell company that is used to launder money. This can make it appear as if the accountant is the owner or beneficiary of the funds, while the actual owner or beneficiary is hidden.
References:
Money Laundering: What It Is and How to Prevent It - Investopedia, The Process of Laundering Money Revealed: accountants aiding money laundering - Accountancy Age, Accountants' methods Accountants in the anti-money laundering front line, Accountants' obligations
https://www.ojp.gov/pdffiles1/Digitization/119840NCJRS.pdf

Explanation
"A sound Customer Due Diligence (CDD) program is one of the best ways to prevent money laundering and other financial crime."