Rendering an application on multiple device sizes

Hey guys, I'm pretty new to Swift and I'm currently working on an iOS project with Swift 4.2. I'm having issues with rendering my application on multiple devices. I started the application with an iPhone 11 and it looks perfect on this iPhone, however when i switch devices to and iPhone 8 or iPhone 12 some elements go off the screen or look way too small. Any tips for this? And should i be editing this directly in the main.storyboard? Thanks for the help!

And should i be editing this directly in the main.storyboard? 

You added the tag SwiftUI, but if you are using Main.storyboard, you are not using SwiftUI, but using UIKit.

And the answer is YES. What you have written happens when you have not added enough constraint on the storyboard.
It is very hard to say something sure without seeing your storyboard settings, but better try to add/edit constraints on the storyboard.
If there are some warnings generated while build time, they can be some hint about how to fix.
Rendering an application on multiple device sizes
 
 
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