Questions about NBitcoin usage

I’m trying to use the NBitcoin library for sending raw transactions and making wallets. Do I need to have a full Bitcoin Core node for it to work or is it already connected to the Bitcoin network?

Most features in NBitcoin need a Full Node, but they mentioned an "SPV Wallet Implementation" in the docs. SPV stands for Simple Payment Verification, similar to what Electrum uses. So, you might not need a full node for everything. You can also look into Electrum's protocol to connect to its public servers. Some wallets do that. Just a heads up, DYOR since nobody's gonna do that for you unless they’ve got a working setup.

You really don’t need an SPV client just to broadcast a transaction. There are simpler ways. Check out my project Bitcoin.Net and its MinimalClient. It has a UI for sending txs too. But I wouldn’t suggest using it for wallet creation right now because I’m tweaking the ECC implementation, and it may not be the safest choice.