I’m not sure that you can. At least not in the way you’re wanting. If you use something other than an Apple, there should be an app you can download that adds a few extra items and maybe even a save changer (?). Feel free to fact check me on this though.
There is a save editor on the Apple App Store. Theres a good one and a crappy one. But no mods or SD-EV. Android has some mods, I’m not sure if they have the SDV-EV. Someone with Android will hopefully help you soon.
I haven’t tried it myself but I know some people have difficulty because smapi is still in testing and might not work on a devices. There’s also a list linked there with working and non working mods. SVE seems to work.