How can I download an older version of Xcode? I am trying to download Xcode from the App Store, but it says that I have to have a newer version of macOS. But I don't have enough space on my computer to upgrade. Its like 8 gigs or something like that and if I only could download Xcode that was compatible with macOS Sierra that would be nice.
If you have a developers account you can download past versions of Xcode from here...

A developers account is $99 per year if you want to open one. There used to be an option for a free developers account. If just required an apple password. If you have an apple id, you might try visiting the link included here.