Presume the company is making an offer to it's employees of voluntary severance, if so then this is available to all employees to make an application and have the application measured against various criteria which should be disclosed by the business, it should be fair and there should be a right of appeal.
Part of any decision to release an employee would be the value of the employee to the scaled down business, any particular skills that would be hard to replace and so on.
If it is involuntary redundancy then staff members will be selected, usually but not always based on last in first out however this is not always the case.
If you have a trade union then you should get in touch and seek a collective bargaining, if not you need an employee nominated representative.