Use a harmless reproduction when possible. Crop a screenshot to the relevant error and remove names, phone numbers, message text, and unrelated account details. A small redacted sample is more useful than an entire contact list or conversation archive.
Keep the time, safe error code, and request or resource reference visible. Review files before attaching them to the support chat, including hidden spreadsheet columns and log headers. If the issue cannot be explained without sensitive evidence, ask support what specific portion is needed before uploading it.