So long as your mobile phone supports fingerprint logins, then yes, you can.
You still need to set a 5-digit PIN for your Yoti app first.
Next, make sure fingerprint login is activated on your phone. Check your phone’s settings (this will be slightly different depending on the type of phone you have).
Then, in your Yoti app, go to the More > Settings > Account settings > Login Settings, and turn on Use fingerprint.
Once you’ve done this, you can log in to the Yoti app using your fingerprint instead of your PIN.