I assume you're referring to the Federal tax credit for electric vehicles as shown at https://www.fueleconomy.gov/feg/taxevb.shtml . That will be claimed on Form 8936 for the year the vehicle was "placed in service". I assume your vehicle wasn't "placed in service" in 2021, thus you'll have to claim the credit on your 2022 tax return filed in 2023. (I also assume it's a 4-wheeled vehicle; the credit for 2-wheeled vehicles expired at the end of 2021.)
You can do it either way: Wait till you file next year and get the $7,500 credit then, or reduce your withholding to get it back during the year. However, as it is not a fully refundable credit and has other potential limitations, it may be safer to wait till next year.
