My vitamin d is 23 l is it ok to still take my multivitamin that has 400iu vitamin d & want to take vitamin d3 1000 ?

Not a problem: The amount of vitamin D in a multivitamin is a small daily requirement dose. If you are being prescribed a supplement for low vitamin D levels, the amount in your daily vitamin is not significant. You can continue it without worry. Please don't treat your own vitamin D levels - too much vitamin D can have toxic side effects as it builds up in your body.