Postcards can usually be delivered within 3-20 days, mainly because postcards are a kind of ordinary mail service, and the delivery speed of post offices will be arranged according to factors such as distance, traffic conditions and weather. Generally speaking, postcards that are near can be delivered within 3 days, and those that are far away take longer.
In case of epidemic situation, natural disasters and other special circumstances, it may affect the delivery time, but the longest time is no more than 20 days.