For system apps, there is an option to "uninstall updates", which I think goes back to the original version when the phone was shipped. The option should be in the settings / apps ... choose app of interest. It may be hidden behind overflow icon (three dots). If you still can't find it let us know your phone and android version, maybe someone can give you more specific instructions.
Uninstalling updates doesn't disable the app, you can still use it (it's just not the latest version and may be missing some features). Disabling does that...then you can no longer use the app and you won't be bothered by app updates for the app and it may disappear from your app drawer. Disabling the app won't uninstall any updates you've installed so won't save any space.
If your goal is to save storage and you don't need the app, you can do both (in order);
1 - uninstall updates
2 - disable app.
3rd party apps are a different story (you can uninstall them... but options for going to previous version are a lot trickier).