It seems that you don't know how actually Bitcoin works and how freebitco.in works.
Don't focus on freebitco.in it's not a wallet so don't call it a wallet you shouldn't worry about your address from freebitco.in if you see your balance there you can withdraw them to your own wallet.

Sample wallet: Electrum or mycelium the address generate from these wallets as your BTC address then you can send bitcoin to these addresses or use them as your receiving address. Like sample, you are withdrawing BTC from a website like freebitco.in use the address generated from electrum or mycelium wallet.
Once you receive bitcoin from these wallets you can spend and send or pay Bitcoin to any merchant online that accept bitcoin as payment.

Check this infographic's how Bitcoin transaction works so that you can understand what it is.

And check this video: Bitcoin explained and made simple