For the best results, the plants should be within the bulb’s effective light range, which is typically around 25cm -90cm. You can find more information on light distance here: https://grow-gang.com/blogs/blog/how-close-to-keep-your-grow-lights.
Your plants will give you feedback: if they appear to be stretching towards the light, they need to be moved closer. If they show signs of stress (brown or yellowing leaves), move the light further away.