To start using The Encryption FieldType, you'll need to set it up as a Custom Field within either Member Fields or Channel Entries.
Regardless of which installation route(s) you take, you'll be provided with the below configuration for your fields:
The actual HTML element to generate within your forms. You have 3 options
The Member Roles you want to decrypt the data for. You can select multiple Roles that are >= 5.
Super Admin is always decrypted.
What you want displayed when/if a member views the encrypted data but CAN NOT view the decrypted value. Defaults to ******
The maximum character length to allow for the input field