If you want to send your BTC coins to another BTC wallet, you need to use "Send" option in the main application menu. You need to know the destination BTC wallet address for this purpose. Do not forget that inside light wallet application you can make only one currency direct transactions, for example, you are not able to make straight BTC to BTG transaction. Pay attention to the transaction fee, if you set up low commission fee your transaction will be unconfirmed and stuck in the mempool. The transaction fee (commission) is some amount of coins that you're paying to the miners for the including your transaction into the blockchain block. You may find recommended fees here: https://bitcoinfees.earn.com.