Hello I created an Electrum wallet and transferred some btc to this wallet. But how can I send btc from there?
You got good replies that teach you how to move/ transfer your bitcoin, but I checked and nobody told you about Bitcoin testnet. If you are worrying about mistake that can cause your bitcoin loss, you can use a Bitcoin testnet to practice. When you are doing it well, familiar with broadcasting a Bitcoin transaction on testnet, you can do it similarly on Bitcoin mainnet.