Seed phrase

12 or 24 words that can rebuild your wallet on any device. Also called a recovery phrase.

A seed phrase is a list of 12 or 24 words, chosen from a standard list of 2,048 words (the BIP-39 list), that your wallet generates when you create it. The words, in order, can regenerate every private key in that wallet.

That makes the seed phrase the most important thing to protect. Anyone who has it can take everything in the wallet, from anywhere in the world, without your device. Nobody legitimate will ever ask you for it.