Mostly like you would remove any other application from linux.
-
apt-get remove package will remove the binaries. Configuration / dependencies will not be removed.
-
apt-get purge package will remove everything regarding the package (except for dependencies).
To remove dependencies
apt-get autoremove has to be executed afterwards.
To completely remove any traces of electrum at all you can overwrite the file several times to make it unrecoverable.
You can read more about unrecoverably deleting here:
https://www.tecmint.com/permanently-and-securely-delete-files-directories-linux/
