Orders before 3 p.m. qualify for same-day delivery.
Tips
usage
当天 = 'that same day' (read dàngtiān, not dāngtiān — the 4th-tone reading is fixed for this sense). 送达 = 'to deliver' (CC-CEDICT). Key ad-copy term for 京东, SF Express, and same-city grocery apps like 美团买菜 and 盒马.