Send by text lets you send crypto to someone's phone number instead of a wallet address.
If they're already on Ulys, it goes straight to their wallet. If they aren't, they get a text and claim it by signing up with that number.
You can send USDC and other crypto this way, but not assets on Solana or Bitcoin. You'll see any fees before you confirm.
Ulys never holds the money. Until someone claims it, it stays in your wallet.