If you are seeing the "Incorrect Format" error then you are probably attempting to import your Secret Recovery Phrase in the Private Key importer. These are 2 different things which is why the format is incorrect.
Phantom can only use 1 Secret Phrase at a time, so if you would like to use your Secret Phrase you can either install the Phantom wallet on a different browser/mobile device and use the Secret phrase (or) if you would like to continue with the current browser, you need to follow these steps:
- Back up your Phantom secret phrase by going into settings and clicking "Show Secret Recovery Phrase". Make sure you write this down and keep it in a safe place if you haven't already.
- Go back into settings and click "Reset Secret Recovery Phrase"
- Import your secret phrase
DO NOT share your Secret Recovery Phrase with anyone! If someone has access to your secret phrase, they will have access to your wallet. Phantom support will NEVER ask you for your secret phrase or your private key.