For your security, npm may require additional verification to allow you to log in to your account. If you do not have two-factor authentication enabled, you may be asked to verify yourself with a one-time password sent to the email address configured for your account.
You'll be prompted for a one-time password that was sent to your email.
Check your email account for an email from npm containing your one-time password (the subject will begin "OTP for logging in to your account").
Enter the digits from your email in your one-time password field.
Enabling two-factor authentication
To avoid this additional login step, with a one-time password sent to you via e-mail, you can configure two-factor authentication with a device (2FA) instead.