Making several assumptions including that you’re investing for the long term;
I’d open an account with Fidelity Investments (good web site, low fees (especially with a million on hand.)
Then I’d;
1. Put 3 to 6 Months living expenses in a safety fund invested in a Money Market fund or tax free MMF depending on your income. e.g FDRXX.
2. Max out any 401k’s and IRA’s. Invest these funds in an S&P500 index fund.
3. Subtract my age from 110 and put that percentage of the million dollars in an intermediate gov’t bond fund. e.g. FSTGX.
4. Put the balance in a total market equity index fund. e.g. FSEMX
BTW - I’d do the same with $10,000 $100,000 or $10,000,000. That would be a good starting point.
I.e age 30 80% in stocks 20% in bonds. Age 90 20% in stocks 80% in bonds.