Quick principle
Use the official online or phone route first when it can solve the task. If you need in-person help, schedule the appointment and bring a complete file.
Use the letter as your roadmap
Find the letter number and response instructions. Start only from IRS.gov; avoid links in unexpected texts, emails or social posts.
Gather return information
You may need the letter, the return identified in it, a prior-year return and supporting forms such as W-2 or 1099.
Schedule only when directed
If the letter or IRS representative directs you to an office, call for an appointment and confirm the exact identification documents required.