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You should only need your EV purchase paperwork in case you are audited and need to provide verification that you purchased the vehicle in the calendar year.
Otherwise all you should need is to provide the answers for questions on the tax form.
You’ll need to file the IRS form 8936 along with your taxes. Since you say you use an accountant, just inform them you purchased an EV that’s subject to the federal tax credit and they’ll do the rest.