Pick a brokerage. Look for one with no account fees and $0 commissions .
Since children have a very long time horizon, you can afford to be aggressive.
Buy companies they know and use (like Disney , Apple , or Roblox ). This makes the gift "real" and teaches them about ownership.
The first step is deciding where the money will live. Each option has different tax and control rules.
Safer and easier. Buying an S&P 500 ETF (like VOO or SPY) gives them a tiny piece of the 500 biggest companies in the U.S.
You will need the grandchild’s Social Security Number and birthdate to open any custodial account.
If the grandchild has any earned income (like a summer job), you can open this. It offers tax-free growth for life—a massive advantage for a young person.