My wife needs me to act as her advisor when meeting with her employer about problems at work
If it is a private employer and there isn't a union involved, attendance at company meetings would be a matter of company policy. Any form required for attendance at a meeting would be provided by the company. If the meetings are held in a private setting, there is
generally no legal requirement to allow a spouse to be present. I suggest reviewing any company employment contracts/handbooks/documents for applicable policies.