This depends on a few things. First, you have different degrees of sight impairment: no vision or residual vision, meaning that the person’s vision isn’t completely gone but their vision is impaired to a degree that they’re considered legally blind. Second - if I’m recalling the education I received from a charity right - more people lose their sight later on in life than are born visually impaired. And according to some quick Google research, people whose vision begins to recede over the age of seven do tend to retain memories of how things looked. So you could work off memory, along with describing the input from other senses: touch, smell, sound, taste. Or work off those senses alone if you’re writing a character who is blind from birth.
It would probably help to search and read books by and about blind people, just so you can familiarize yourself with what everyday life is like from them. Blindness has been around a long time, and looking into the past and present treatment and views on it can help give you a wider perspective on what a blind character would have to face in terms of attitudes and faulty ideas. Those who have been born blind would not have and may not want a sense of what seeing is like, as it has never been a part of their lives.
Some books links:
And here are some other links:
Yooo… more blind writing refs (my favorite kind because of reasons that involve my story, also writing blind characters is hella fun to me for some reason).
My best advice is to pay attention to all the other senses—you can get a hell of a lot of description out of them once you start thinking beyond what things look like.