Thats not entirely true, you can import private key also to software wallets like electrum, multibit or bitcoin core. You don't need to import paper wallet to online wallets.
Better to keep you coins offline, paper wallet is great but software wallets are second to best and third one are online wallets.
I would like to know about paper wallet. Because it is completely offline. But I have doubt, How to do transfers (Send and Recieve).
Paper wallet like any other has private and public keys. The private key should be kept secret, because it gives you full control over the funds, while the public key is used to receive funds.
To request a payment or send money to your paper wallet, simply choose an address and send it to the payer. You can also carry a qr code with you and let someone scan it with their phone.
When you decide to make payments you should use a desktop wallet like electrum, add the private key using the "swipe" function, do all the payments and transfer the rest of the money to a new offline address.