You should google Older Workers Benefit Protection Act.
OWBPA includes
The employer must not use undue pressure to get the worker to sign a waiver of the individual’s rights;
The proposed waiver must be succinct, accurate, and reasonably understandable to an ordinary person;
Any release of claims must be in writing;
The waiver must explicitly state that the employee is releasing their claims under the ADEA;
The employer must encourage the employee to consult with an attorney before signing the agreement; and
The employer must give the employee up to 21 days to consider the severance offer (or 45 days if the termination is part of a layoff of more than one employee). Upon signing, the employee has seven days to revoke their signature
In addition to the above, an employer claiming to implement a reduction in force, defined as a termination of two or more employees, must also provide the terminated employee with the following information:
The job titles and ages of any other workers in the employee’s unit or department who are also being laid off;
The job titles and ages of all other workers in the employee’s unit or department who are being retained, that is, who are not being laid off; and
The eligibility factors used to determine who was laid off and who was retained