Thank you for contacting us. Since mSecure connects to it's own account system in order to handle licensing and syncing of information, Family Sharing isn't really a compatible feature for version 5. Instead, if you own a license, you would simply download mSecure onto all of your devices, then sign in to the same paid account. The Pro license covers all of your personal and immediate family member's devices, so you only need to purchase one license.
With everyone signed in to the same account, your information will be synced between all of your family members. However, if you were to do this, everyone would have full access to all of the information in the account. Currently, there is no way to only share certain records stored in an account. Many of our customers who wish to share information with their family want to only share certain sets of data, but that won't be possible until the next version of mSecure is released.
If you are ok with sharing all of the data in the account, you can simply download mSecure 5 onto all of your family's and sign in to the same account. After signing in, the data in the account should sync into each mSecure app. From that point on, changes you both make will be synced to each other's devices depending on the sync feature you have chosen for the account.