Whenever you have a broker account invested in stocks, bonds, mutual funds etc., you should get a series of statements or a combined statement at the end of the year reporting your taxable income; a 1099-B, 1099-DIV, maybe a 1099-INT. You pay income tax on certain interest and dividends, and capital gains that were realized during the year. When you sell investments to withdraw cash, that realizes or locks in some gains (if you sold the investments for more than you paid) or you will take a loss (if you sold the investments for less than you paid) and all that gets reported on your tax return at the end of the year in the usual way.
Then, whatever you do with the money after that, is completely separate from the process of cashing it out.
