Zmień kolor TextInputLayout
android:textColorHint="@color/your_color"
TechTalk
android:textColorHint="@color/your_color"
<com.google.android.material.textfield.TextInputLayout
app:boxBackgroundColor="@android:color/transparent"
android:background="@android:color/transparent">
<com.google.android.material.textfield.TextInputEditText/>
</com.google.android.material.textfield.TextInputLayout>