This app provides a basic asymmetric encryption for your messages.
How it works? Both you and a message recipient must have EncryptIt app installed. Recipient should share their public key (generated automatically within the app) with you. After you add recipient's key as a contact, you may create an encrypted message for this recipient. Only recipient can read a message encrypted with a specific public key.
This app is not a messenger. It has even no internet access. You should use any other communication app to actually send the message, by copying the encrypted text to it.
Disclaimer: the app uses standard Android encryption providers (RSA) for the encryption. There is no any specific warranty regarding cryptographic stability and resistance to hacking for these algorithms and details of their implementation. The safety of your private data is still your responsibility.