I backed up my private keys. Can I use these private keys in other wallets too? Let's just say I've backed up the seed words of your wallet. What if the electrum project is canceled in the future?
By looking at Bitcoin's address, can we tell which wallet was created? Every wallet seems to be creating a unique address for itself. But money can be transferred between different wallets.
For example, I backed up private keys in the electrum wallet. Can I use the addresses in the electrum in a different wallet using these private keys?
As long as you have a copy of the electrum software you are good.
Possessing just the address does not give you the power to spend the bitcoins sent there. If it were designed like that your bitcoins could be spent by anybody!
When you spend bitcoins coins may be drawn from various addresses so anyone looking at the blockchain could infer that these addresses belong to the same wallet.