The choice of road bikes has more stringent requirements than mountain bikes, because road bikes have higher requirements for riding postures, and inappropriate choices will make your riding very difficult.
First you need to choose the right size frame. If your height is between the height of two size models, choose a frame that is biased towards small size. If the frame is smaller, you can make up for it by lengthening the handle, and the car will be more stable. If you have too big frame, you will have almost no room to make up, because shortening the handle will make the frame too flexible.
Try to use the middle and high-end grades as much as possible, because the low-end hand-changing head shift requires a lot of power, and the handle feel is relatively poor, or relatively large, and there is no room for adjustment, your hand can't hold it at all. If the budget is limited, the front and back dialing do not need to be too high-end, and can be matched with the hand change.
Choose a pair of rounded feet to avoid scratching your legs when you get off the bus or when you are in the cart.