bitcoins aren't physical things... Basically, a wallet is just a piece of software to manage your private keys, generating transactions, broadcasting.
If electrum updates, nothing happens. You either chose to install the update or not (which usually goes seamingly, and if it goes wrong, you just use the seed words you wrote down when you first installed electrum, and restore your wallet... The worst thing that'll happen is the fact that you lost your labels).
If you chose to run an outdated version, you won't have access to the latest bugfixes, patches and new features, but usually,it's not a real problem.
PS: I'm also a big electrum fan. Core might be a tad bit better, since you synced and verified the full blockchain, but electrum is still good, since your private keys don't leave your computer, and can be encrypted with a strong password and 2fa
Electrum is a good desktop wallet, even better when used with a Trezor so your private keys are always kept offline.
But how to find out the private keys here. Is it same as seed?
No the seed is different from the keys. If you go to the address tab and rightclick on an address you can let the wallet show you its private key.
Ok.
Is it okay if I just save wallet, seed and password in pendrives in a safe place rather than saving private keys?
Saving the seed is the most important thing. You can use it to make a new wallet that doesn't have a password if you lose your original password. However, there's no harm in backing up the wallet and password too.
Make multiple backups on multiple types of backup media in case one gets corrupted, and make sure they work before relying on them. Pen drives can stop working, DVDs can get broken. If you have backups on a pendrive, DVD, and memory card then if one of them gets broken you can still use the others. No one backup media is 100% reliable.