hold btc for 2 years with Electrum

[10_sjdovn_10]

then write down the seed phrase, not individual private keys

It makes no difference in this case,  private keys are software independent.
Maybe I have an address generated in electrum but I don't want to use electrum after that.

[Stalker22]

then write down the seed phrase, not individual private keys

It makes no difference in this case,  private keys are software independent.
Maybe I have an address generated in electrum but I don't want to use electrum after that.

Have you read the answers above this?
As far as I understand, you don't have to use Electrum to recover addresses from backup seed phrase.

...you can use any open source piece of software with two very minor changes as explained by pooya87 above to restore an Electrum seed phrase. For example, with https://github.com/iancoleman/bip39, simply open src/js/jsbip39.js, change line 116 to return true; and at line 144 change the word "mnemonic" to the word "electrum". The derivation paths will be different (m/0 for legacy and m/0'/0 for segwit), but it will generate your Electrum addresses just fine.

[o_e_l_e_o]

As far as I understand, you don't have to use Electrum to recover addresses from backup seed phrase.

So we need to make sure we aren't mixing up individual private keys and seed phrases here.

Individual private keys can be imported in to any piece of software which allows you to import individual keys and supports the correct address type. This is pretty much any wallet for P2PKH (1) and P2SH (3) addresses, but there a still a few wallets which do not support P2WPKH (bc1) addresses.

BIP39 seed phrases can be imported in to any other BIP39 supporting wallet (which is almost all of them), again with the caveat that it will derive the correct address type for you. Electrum seed phrases can only be imported back in to Electrum and one or two other wallets which accept Electrum seed phrases, although it is easy to extract the private keys from an Electrum seed phrase even without one of these wallets.

[Stalker22]

As far as I understand, you don't have to use Electrum to recover addresses from backup seed phrase.

So we need to make sure we aren't mixing up individual private keys and seed phrases here.

Individual private keys can be imported in to any piece of software which allows you to import individual keys and supports the correct address type. This is pretty much any wallet for P2PKH (1) and P2SH (3) addresses, but there a still a few wallets which do not support P2WPKH (bc1) addresses.

BIP39 seed phrases can be imported in to any other BIP39 supporting wallet (which is almost all of them), again with the caveat that it will derive the correct address type for you. Electrum seed phrases can only be imported back in to Electrum and one or two other wallets which accept Electrum seed phrases, although it is easy to extract the private keys from an Electrum seed phrase even without one of these wallets.

I got it, chief.
Individual private key => Single address
Mnemonic seed phrase => Multiple individual adresses/private keys

Is it ok to call BIP39 supporting wallet also a HD wallet (Hierarchical Deterministic Wallet) or does it refer to something else?

[o_e_l_e_o]

Is it ok to call BIP39 supporting wallet also a HD wallet (Hierarchical Deterministic Wallet) or does it refer to something else?

Yes, but they are not synonymous.

HD wallets are any wallets which produce keys in a deterministic fashion.
BIP39 describes the implementation of using a series of words as the seed to this deterministic process.

So all BIP39 wallets are HD wallets, but not all HD wallets are BIP39 wallets. Bitcoin Core, as the most notable example, is HD but does not use BIP39 seed phrases.