For two people to see and log the same data, sign in with the same Macuta account on your devices. Sync, on every plan, keeps the devices with the same data.
The data is encrypted. With an email account, the password you sign in with also opens the data, so whoever shares the account needs to know it. With a Google account, you need to sign in with the same Google account. Not even Kioxke can read your data, so there is no other way to share it.