I have re-read your question a few times - withholding is not normally done on stock sales thru a broker, so I will assume you had stock options you exercised then sold? If not, disregard my answer - if yes, you will have the income from the options and withholding reported on your W-2, so when you enter that information into the software, you will be recording the withholding. Then, assuming you sold the stock, you will report the sale on Schedule D - important to realize the basis in your shares will be the option exercise price that was included in your taxable income on your W-2 - if exercised at the current market price then immediately sold, you probably will have little gain or loss on this sale.
