data?.data resolves to either a Uri or null. Kotlin treats null as being part of the type system, so the inferred type is Uri? (? indicating that the value might be null). However, openInputStream() does not support null. So, you need to check to see if imageUri is null and, if it is, do not try to use it.

For example, you could use a safe call (?.) with let():

data?.data?.let { imageUri ->
  val imageStream = contentResolver.openInputStream(imageUri)
  val selectedImage = BitmapFactory.decodeStream(imageStream)
  profile_page_pimage.setImageBitmap(selectedImage)
}

Now, if you did not get a Uri from data?.data, you will not crash when trying to read in the non-existent content.

You need to add the null-safety mark !! , so your code you should be like ths

val imageStream = contentResolver.openInputStream(imageUri!!)

I get an error message:

required type Uri 
found Uri?

My code:
val imageUri = data?.data
val imageStream = contentResolver.openInputStream(imageUri)
val selectedImage = BitmapFactory.decodeStream(imageStream)
profile_page_pimage.setImageBitmap(selectedImage)

This is error message