In addition to the above posts, there is another currency that supports Electrum(Not the fork of Electrum.)
It also supports tBTC when you enable testnet on Electrum but this coin has no value it usually use only for testing and development.
If you want to test something want to learn how to use it you can get free tBTC from this
testnet faucet list.
BTC for the mainet, while tBTC for the testnet. Everything is still about bitcoin, but tBTC is not a real bitcoin. tBTC is not another currency, it is only just used to know how bitcoin transaction is, using the testnet version. I believe you know this, but I just want to point out that tBTC is still all about bitcoin, but not the real bitcoin.
But to use tBTC you need a separate program in Windows OS or you need a separate command which is --testnet for CLI and thus it is a separate currency with a separate program just like a hard fork.
The official electrum wallet is developed mainly for bitcoin and all forks for other altcoins are not of the same quality or number of reviews and therefore you cannot trust it exactly as you trust electrium. For altcoin it is better to manage them using HW.
If you install Electrum on your computer, the testnet version will also be installed along. Although, no the same wallet, they are both different but installed at the same time.