Generally, this is a question of your current health level. For an elderly person, recommendations for exercise therapy may look like "walk 500 m" or even a hundred meters a day if there are problems with the heart and musculoskeletal system.
For a healthy person of working age, of course, the recommendations are clearly higher. I have not met any directly rigid norms. There is a long-standing advice from books on healthy lifestyle - 10 km per day. But this is so, it is written with a pitchfork like 8 glasses of water)))
I advise you to carefully read the WHO Global Recommendations on Physical Activity for Health
Hello! Once upon a time in the polyclink I saw a poster on which it was written about 10 km a day. I think this is a perfectly normal figure. But at the same time I agree that the most likely sign is speed rather than mileage.
The World Health Organization recommends that everyone take a daily walk of at least 8,000 steps. Accordingly, you must walk at least 3 km. per day to maintain the body in a sufficient tone for a full life.