Do I need to do the effects of the item, or just the appearance?

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We need to make an example with effects or attack the items, for example, if I want to make a staff that releases a purple energy, do I need to make this attack?
Another question, do I need to model my item in a separate image for each side, or can I place the item, along with the effects of the skills, along with the example in the game?
Last question, does the background need to be green or transparent? it may be silly to ask, but I don't want to make mistakes!