That depends on the wallet you choose to use.

If you are using Bitcoin Core, then there are no "words".  There is only the wallet file, and any private keys that you have chosen to export.

If you are using Electrum, then you need to secure your seed words AND your wallet file.

If you are using a Trezor hardware wallet, then you need to secure your seed words AND your device.

Each wallet comes with its own features and it's own vulnerabilities. You should take the time to understand the wallet that you choose, and then make sure that you secure it so that:

1. You do not lose access to the important information for that wallet.

2. You do not leak the important information to anybody else.