Yes. At the Android native level there are attributes such as android:labelFor and android:hint.
See Accessibility on Android in the Xamarin docs and Principles for improving app accesssibility in the Android developer documentation.
At the Xamarin Forms level these and their iOS and UWP equivalents are exposed as cross-platform properties via Automation Properties in Xamarin.Forms to name or describe an element, or to point to another control to label the element.