This is a paid asset, but now you can download Automatic UI Anchoring for FREE, but please remember this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Automatic UI Anchoring v1.0
Have you ever made the UI for your game only to realize that you now have to manually anchor many of the UI objects so that their aspect ratios are persevered when scaling to different screen sizes?
I know I have and if you have too look no further this is the perfect plugin for you!
You can use Automatic UI Anchoring For Unity 3D to set the anchor positions of UI elements by simply selecting them in the hierarchy view and then selecting “Tools->Automatic UI Anchoring->Anchor Selected UI Objects” from the top bar or pressing the hotkey which by default is “F1” on your keyboard!
This tool is also available on GitHub at:
https://github.com/AndrewCodes200/Automatic-UI-Anchoring-For-Unity-3D