3 months ago, i made a Electrum wallet and let it to make my seeds itself from default option. Should i made another wallet with my words? Is my bitcoin safe?
Is it possible electerum sends seeds to a certain server for the DeveloperS?
No. The way Electrum generates your seed is 100% safe and no one other than you will be able to see it.
You also shouldn't "create a seed" by your own. This is called a "brain wallet" and it can be way dangerous than a normal one generated by the software.
"Brain Wallets Are Not Secure and ‘No One Should Use Them,’ Says Study"
https://news.bitcoin.com/brain-wallets-not-secure-no-one-use-says-study/