age is a command-line tool that encrypts files. These files are binary, add around 200 bytes of overhead per recipient, together with 16 bytes every 64K of plaintext.
age doesn’t offer disk encryption. Instead, it’s designed to be a simple, modern, and secure command-line file encryption tool. File encryption helps protect your data by encrypting it. Only someone with the right encryption key (such as a passphrase) can decrypt it.