What is the best way to send a raw transaction via a webserver, what role does a RPC play in this? Is a bitcoin-RPC used to send/transmit a raw transaction to the bitcoin network? Can the process of signing/creating a raw transaction be done with a RPC too? Assuming I attempt to transmit a signed raw transaction via a webserver to the bitcoin network, what do I have to keep in mind?
If you have a local bitcoin node (i.e. bitcoind running on the webserver), you can use the RPC command
sendrawtransaction in order to send a transaction through your node to the network. Alternatively you can use a third party transaction broadcasting service like those offered by blockchain.info and blockcypher.com. Lastly, you could attempt to speak the Bitcoin P2P protocol and send the transaction directly to nodes on the network.
a link to some discussion without full client here: