Use ～と見える in written or formal spoken register when you infer something from observable evidence — a report, someone's behavior, the state of a document. It is more detached and literary than ようだ／らしい, so it fits written reports, minutes, and analytical email prose; the conjunctive form ～と見えて is very common for linking the inference to its visible result. Avoid it for your own internal states (×私は疲れていると見える).