If you would like to authorize someone to represent your company, here is a sample authorization letter to represent a company.
[Recipient’s Designation or Organization]
Subject: Authorization To [Task or Responsibility]
This letter is to authorize [Name of Entrusted Person] to dispense of the mentioned responsibilities. They will be acting on behalf of [Your Company] until further notice or till [Date]. They have full authority with regard to this task and represent our business for the same.