How To Write A Letter Of Complaint To Your Employer . For harassment concerns, you’ll need a sample workplace harassment complaint letter for that. Encourage hr to take corrective action. Download Employee Complaint Letter About Boss Sample Templates from www.sample-templatess123.com This may include receipts, warranties, cheques, pictures, videos if there are any. So, when writing a letter complaining about manager behavior, you need to ensure that you have your name, address, the name of the manager and the account of events laid out. Attach copies of the necessary and relevant documents.