I am new to Bitcoin investment trading, I recently invested $500 in 401trade.com and got $19,000 setting in their account, I went to withdraw $18,000 and they said I had to pay $200 in taxes and gave a different bitcoin address to send it to. I had previously asked them if there was anymore fees or charges before withdraw the money and they said no. I figured they could take it out of the amount being received or I could pay it when I got the money. I've never done this before and worried I'm being scammed.
You are definitely being scammed - you should write off the $500 as an expensive lesson and never deal with these people again.
No legitimate company operates in such a way. $200 on a $18500 profit is also not what you would pay under any real tax structure, and even if you had to pay it, it would be paid alongside your regular taxes.
Even if the company had to deduct it and file it separately, they could do so by deducting it from the "profits".
If they had a way to turn $500 into $19000, they wouldn't need $500 from you to do so - they'd already be amongst the richest people in the world.