Electrum does not generate a bip39 seed phrase, it uses an Electrum seed and you cannot import it into most wallet softwares, as far as i know, only BlueWallet supports importing an Electrum seed phrase. So you cannot import it into Metamask or TrustWallet.
I know we can import other wallets with BIP39 to Electrum wallet, choose BIP39 when importing but the process to import Electrum wallet to other wallets is different flow because Electrum wallet use its own seed phrase, not use BIP39.
We can move bitcoins to another wallet or to export private keys in Electrum, then use private keys for import in other wallets.
To export private keys, in Electrum.
Wallets > Private keys > Export > Choose CSV or JSON, and export keys.
This step is to export all private keys in the wallet.
If we want to export only one private key for one public address, right click on the Public address, choose Private key, type wallet passwords, and export the private key.