This is considered an investment Expense because the legal fees are secure your investment income. You will include this in your itemized deductions on Schedule A.
Here is how to enter it in TurboTax Online
To enter in TurboTax Deluxe
Go to Deductions & Credits
Scroll to Retirement and Investments
Click Other Investment Expenses
These expenses must be more than 2% of your AGI to be deductible, so you may not see a difference in your calculations.
For more information, see page 8 of IRS publication 529 here: Misc Expenses