Designing an iOS app, do I have to design screens for each device size?

Noob question: I finished designing a couple screens using Sketch's iPhone 8 template which is sized 375x667. Want to make sure it looks good on other screen sizes too. Does the designer also design separate screens for other devices like iPhone 8+, iPhone X, iPad, iPad Pro?

Do you typically create all screen sizes to hand off for developers? Or just one screen size and they figure out the rest?

If this is something I need to do, I'm confused about how to design for other device screens.

For example, in this following screen:

iPhone 8 example

  • What is the best way to design the other screen sizes?
  • Do I need to increase the font size? How do I know how much? Are there guidelines?
  • Does the padding stay the same? Or does it scale proportionately with screen size? Again, are there any guidelines? For example, if iPad increase padding by 2x?

Unclear on how to design for these other screen sizes after I have one. It seems like a lot of work to create individual screens for ALL screen sizes? Is there a more automated way this is done? How do developers expect to receive designs?

Thanks!