From a survey's Submissions view, the Export Submissions button downloads a CSV of every response — one row per submission, one column per question. Select specific rows first and the button switches to Export (N) Submissions, so you can pull just the ones you need instead of the whole set.
The download is named after the form and the date it was generated, so repeat exports don't overwrite each other. CSV is currently the only export format — it opens cleanly in Excel, Google Sheets and Numbers, but a native Excel (.xlsx) export isn't available yet.