You may have relevant information
Letter 5775 asks to schedule a discussion about a federal tax matter unrelated to you. The IRS says it is not a notification that you are under audit or investigation.
Confirm who is contacting you
Contact the employee identified in the letter to ask questions and arrange a time. IRS guidance says the employee will identify themself with a badge at the meeting. Do not volunteer sensitive identifying information before you have confirmed the contact's identity.
Prepare for the conversation
Keep the letter and reference number. Ask what subjects or records the employee wants to discuss so you can distinguish what you know firsthand from what you would need to check. If you need language assistance, tell the IRS when scheduling; it can provide an interpreter.