There are elements in a child's development that we worry about. We compare the feet, legs, posture, manner of sitting down and walking of our child with their peers or with our expectations. But should we worry about everything?
The child is not yet walking independently
Your child is one year old and does not even think about taking the first steps on their own, spending most of the time in a quadrupedal position. And let's focus on that. Let them use the quadrupedal position, because thanks to it they develop their body very well, and the time for independent steps will come when the baby is fully prepared for it. Independent walking, according to the Denver scale, should be achieved at 18 months of age. So until then, let's not panic, but also let's not interfere. What does it mean? Do not force speeding up the child's development, because some "supportive" actions do the opposite. Don't lead them by the hand, don't help them to stand up (you can encourage them by, for example, putting a toy on the sofa, but don't lift the child to an upright position), don't catch them every time they fall from standing position onto their bottom. The toddler must learn the feel of their own body, they have to crouch, get up, fall down on their own, because thanks to this they train keeping balance.
Flat feet in a one-year-old toddler
Are you sure that what you see is flat feet? A flat foot in a child under 3 years of age is not unusual, it is simply physiology. Let's not compare their foot with that of an older 7-year-old kid. Children, apart from the fact that their bones and joints are still very flexible, and the muscles and ligaments are just beginning to strengthen through such a difficult activity as independent walking, also have the so-called fat pads that effectively hide the arch of the foot, and their main task is cushioning. This additional fat is absorbed by the age of 3, by then the muscles and ligaments will also become strong enough to support the very complex structure of the child's foot. How to support and not hinder the development of the foot? Forget about orthopedic, stiff, heavy shoes that passively support the foot and where the foot has to adapt to the shoe and not the other way around. Let your child experience many sensory experiences, let them run on various surfaces barefoot, and when they have to put shoes on, choose light ones, with a flexible sole, made of leather, with a healthy foot certificate, where the shoe adjusts to the foot's work.