You can edit the default Client ID Prefix for your account in the User Profile, Application Settings Tab.

For new accounts, the default prefix is 01. For example, for a new user account, when a Client ID is assigned, it will begin with the prefix (01) and then be auto-numbered. For example, 010001, 010002, 010003, etc.

All clients with a Client ID will be included in the Total Clients count on the Dashboard.