Information
The macOS _MUST_ be configured to require at least one numeric character be used when a password is created.
This rule enforces password complexity by requiring users to set passwords that are less vulnerable to malicious users.
NOTE: The guidance for password based authentication in NIST 800-53 (Rev 5) and NIST 800-63B state that complexity rules should be organizationally defined. The values defined are based off of common complexity values. But your organization may define its own password complexity rules.
Solution
This is implemented by a Configuration Profile.
mobileconfig profile info:
com.apple.mobiledevice.passwordpolicy:
requireAlphanumeric:
True