I recently opened a bank account for one kid and was planning to put the money into it. Was also considering opening a brokerage account for them so that they understand investing. I don't want this gift to cause problems for them in future by being counted against inheritance limits (in the small chance that we actually hit it).
I read about the good to file 709 for documentation purpose here https://www.schwab.com/learn/story/sharing-wealth-how-lifetime-gift-tax-exemption-works
