A change address has nothing special, It's just like any other address but since your software generate them separately, you should give people the receiving addresses so the wallet could manage everything properly. You will be able to spend whatever you have in your wallet regardless If they are spread between multiple receiving addresses. I'm not sure I get the second question though, by formatting your phone, you're referring to Mycelium? If yes then why you're referring to the change addresses If you're sending using Electrum? but to answer your question, yes, everything is generated from the seed including the change addresses.
Sorry I didn't state carefully regarding my second question.
If i were to format my phone with Electrum wallet in it, since that change address of 0.2 BTC is in Electrum wallet, would I still be able to spend the 0.2 BTC I have in that change address after reformatting my phone and restore Electrum with just the 12 seed phrases? Or do I need to do some extra backup?
