Recipient decrypt the message using their own private key and verify the sender’s identity and the integrity of the message by decrypting the sender’s digital signatures using the sender’s public key.
You cannot see the private file. Now you can send the file to your friend X. When X receives the file, He/She can open the file if and only if he know the password. He /She can extract the file without any damage. Suppose a person if receives the file or its copy in the middle he cannot access it. He only accesses the host file. He just have the host file not the file that is inside the host.