When creating an Electrum wallet you are shown 12 random words that we call the seed mnemonic, seed or seed words. The seed is ultimately all you need to recover access to your bitcoins and it is very important to write it down on paper and put that paper somewhere safe. In the wallet creation page I actually recommend writing it down in a notebook because loose pieces of paper can get lost.
However, while it is possible to get access to your bitcoins after restoring your wallet from seed if you want to also recover access to your wallet meta data you need to take additional steps. By meta data I mean your transaction and address labels/descriptions and the addresses saved in your contact book.
If you care about both the labels and the contacts then you should periodically backup your wallet file. You can manually backup your wallet file via file menu > save copy. Alternatively you can automate this by having your backup program grab the wallet files from the Electrum wallet directory. Note that wallet file backups should be protected because anyone with access to them can potentially spend your bitcoins. The password you set via wallet menu > password to encrypt the wallet file can provide some protection but denying potential attackers access to the wallet file is even better. Therefore IMO backing up your wallet file to a removable drive is better than backups to the cloud.
If you only care about the labels and don’t mind a little loss of privacy you can enable the label sync plugin. This will mean that you won’t need anything more than the seed when restoring your wallet in future. Electrum will grab your labels from the remote server.