Make, model, year, question? After replacing the battery, the remote may have to be synchronized to the car. The procedure should be outlined in the Owner’s Manual.
It would be useful to have more info. “electronic key battery change” doesn’t even sound like a question.
Usually you just pop the back off and replace the lithium coin cell(s) Mine takes two CR2016s. Yours may be different.
Yes. The electronic key fob battery (batteries) can be changed. Next question?