I downloaded some icons from material.io but they only offer the icons in black. I saw a youtube video where they use to allow you to choose the color. Anyway, I am trying to
https://material.io/icons/ actually does let you download icons in white.
But, depending on what exactly you want to do, there are a few options. If you simply want white icons (and not to change them at runtime), you may find this plugin for Android Studio useful: https://github.com/konifar/android-material-design-icon-generator-plugin
It allows you to generate the material design icons right in Android Studio, in whatever color you want. Another alternative for downloading these icons in different colors is https://materialdesignicons.com/.
If you do want to color the icons at runtime, try something like this:
imageView.setColorFilter(ContextCompat.getColor(context, android.R.color.white),
PorterDuff.Mode.MULTIPLY);