Following the updating of protocols of a cryptocurrency, the fork occurs.
In case the miners don't agree with the update: the chain breaks in two (hard fork).
The old currency will continue with the old protocol, while the new one will follow the update.
Thus was born Bitcoin Cash (from Bitcoin) or Bitcoin SV (from Bitcoin Cash).

Well but how to request the new currency?
Sites like Coinbase do not give the seed to the user so you need to transfer the crypto to a wallet with the seed.
For example Bitcoin from Coinbase on Electrum.
All this must be done BEFORE the fork.

The new coin will have the same seed as the old one, however for security reasons it is better to first transfer the old coin to another wallet and then make the claim (using the old seed).
After that, just import the old seed  ("I already have a seed") into the new coin wallet.
The "daughter" coin will magically appear in the new wallet (for example if I have 3.5 old coins I will have 3.5 new coins).
Thanks for reading and I hope it will be useful to someone for future hard forks!