Is your LN wallet a custodial wallet (e.g., Blue Wallet)?
With Wallet of Satoshi and CoinOS, you can deposit on-chain, and then access (i.e., spend) those funds via LN.
Otherwise, how do I fund a LN ‘wallet’?
You can use an exchange that has support for LN. You can either buy bitcoin and withdraw LN, or some (e.g., Bitfinex) will let you deposit on-chain and withdraw via LN. Some (e.g., Paxful) charge a fee for withdrawing via LN.
Is your LN wallet a custodial wallet (e.g., Blue Wallet)?
With Wallet of Satoshi and CoinOS, you can deposit on-chain, and then access (i.e., spend) those funds via LN.
You can use an exchange that has support for LN. You can either buy bitcoin and withdraw LN, or some (e.g., Bitfinex) will let you deposit on-chain and withdraw via LN. Some (e.g., Paxful) charge a fee for withdrawing via LN.
Exchanges with support for Lightning Network
https://cointastical.github.io/Exchanges-With-LN