Can I transfer BTC from my BTC (address) wallet to my Lightning (address) wallet?

To expand on Pieter’s answer a bit:

To move funds to the Lightning Network, you must send a Bitcoin transaction to move the funds to a wallet that allows the creation of a Lightning Network channel. Transactions that transfer funds to a new wallet will be paid to a Bitcoin address (presumably a bech32 encoded address) as usual.

The Lightning Wallet then allows you to ‘open a channel’ with other nodes on the Lightning Network. Internally, this means that your Lightning wallet collaborates with its counterpart node to generate a special 2/2 multi-signature Bitcoin address. The funds will then be transferred to this address, and with a few extra features, your wallet will now contain funds that can be used to pay bills on the Lightning Network.

As Pieter mentioned, Bitcoin addresses and Lightning invoices are very different, so you don’t have to worry about making a mistake and losing your funds by trying to pay a Lightning invoice with on-chain funds or something like that.