I am talking about the seed phrase. that 26 (25 or 27) words code which is included in the packing of ledger nano wallet. which can be used to recover our wallets. company prints those seeds. so they can steal everyone wallets. -snip-
If you find that the PIN and seed phrase already exists in the Ledger Nano package that you purchased, likely, your Ledger is not safe to use.
A new PIN and seed are generated when you first set up the Ledger on the device connected to it (PC/smartphone).
A recovery phrase is needed if one day the hardware wallet device is damaged, lost, etc. so you can return your assets to the new Ledger. Therefore, don't tell the recovery phrase to other people you don't trust, including those who claim to be from the Ledger.
-snip- my 2nd question was. how can we send Bitcoin if we are offline and not connected to the blockchain? how? I am using electrum and it doesn't work when we are not connected to internet.
so there is no such thing as offline wallet.
Maybe you need to learn what is meant of the Offline Wallet and also how it works.
Offline wallet for savingsAn offline wallet, also known as cold storage, provides the highest level of security for savings. It involves storing a wallet in a secured place that is not connected to the network. When done properly, it can offer a very good protection against computer vulnerabilities. Using an offline wallet in conjunction with backups and encryption is also a good practice. Here is an overview of some approaches.
Offline transaction signingThis approach involves having two computers sharing some parts of the same wallet. The first one must be disconnected from any network. It is the only one that holds the entire wallet and is able to sign transactions. The second computer is connected to the network and only has a watching wallet that can only create unsigned transactions. This way, you can securely issue new transactions with the following steps.
1. Create a new transaction on the online computer and save it on an USB key.
2. Sign the transaction with the offline computer.
3. Send the signed transaction with the online computer.
Because the computer that is connected to the network cannot sign transactions, it cannot be used to withdraw any funds if it is compromised.
Armory can be used to do offline transaction signature.
Another reference:
https://medium.com/@Multicripto/how-to-make-offline-transactions-in-electrum-with-coldcard-wallet-838f84df379a