oof.
Okay.....you can't
really "un-special" a mon. What you can use is PKhex to change the ball on some mon, but it won't always work. Take this as an example: Cherish Ball Mew vs. that other Mew (that you can trade)--even if you change Cherish Ball Mew to "look like" (data-wise) the other Mew, the data is wrong, so you can't trade, battle, GTS; that pertains to "special" mon who have multiple variations. There are some special mon you just can't trade and there's nothing you can do about it. I think Shaymin is one, but I cam't remember, haven't played in about a year.
You can pretty much shiny/un-shiny 80% of mon, but not all.
Now, the "tags" I'm thinking you're talking about, look like these:
and this is probably the other thing you mean:
You can easily remove the black tags--they're just there to help organize. The exception is the red star, that denotes a shiny and you can't "normally" change that.
All of this is complicated stuff that might be above you, but you'll need to learn to use PKHex/BG's projects to edit your mon and you'll have to really, really learn how to edit to make it "legit". An example: I made OP mon to screw the Battle Tree (Wonder Guard Raichu with a Ballon, among many, many other OP fuck-ups....No Guard Fissure cannons), but taking that online? Ha!
Anyway, I'd make sure you aren't being trolled.....like someone requesting a level one Charizrd that knows Origin Pulse.