How can I encrypt my data?

Where can I find the setting to encrypt my form?

Its fully possible to encrypt your forms. Here is a guide on that:

Encrypted Forms and How to Use Them

Note that once your forms are encrypted if you loose your private key, you will have no way of accessing your data. Please backup your private key to a safe place. We do not store private keys so there is nothing we can do in the event of the private key missing.