Does Electrum support altcoins (“cryptocurrencies”)?
No. Electrum only supports Bitcoin.The project has never supported any altcoins, only Bitcoin. However Electrum is free (as in freedom) software with a permissive license, and there are many forks of the software that support specific altcoins. These are separate projects, with their own maintainers, independent of Electrum. We do not review their code or endorse them in any way. If you are a user of these, please direct any and all support requests to their maintainers, instead of us.
What does it mean to “freeze” an address in Electrum?
Assets freezeWhen you freeze an address, the funds in that address will not be used for sending bitcoins. You cannot send bitcoins if you don’t have enough funds in the non-frozen addresses.