Click on Import account from pre-existing seed, as shown below.
Finally, input your seed phrase.
Importing an Account to Fearless Wallet
Unfortunately, Polkadot.js does not allow you to export your seed once you've created your wallet. (More info here). If you haven't saved your seed phrase, you will have to export the JSON file. Have a look at the next tutorial to learn how to import using a JSON file!
If you have already saved your passphrase, open the Fearless Wallet app and click on Settings andthen Accounts.
Then on Add account and Import Account.
Select the correct Source type from the drop down menu to use while importing your account.
If you're importing your wallet using the Mnemonic passphrase, you'll have to choose a name for your account in the Fearless Wallet app.
Instead, if you're using a JSON file, you'll also have to type the password you used to protect that wallet on the Polkadot.js extension!