As long as the Authorization number is entered under Claim Details -> Referral/Authorization tab, you can get it to print in Block 23 on the HCFA claim form. 

There is one catch, if there is also a CLIA number, the CLIA number will take precedence:

The way to get this Authorization number to print on the paper claim is to suppress the CLIA number. Since they share the same block on the printed form, the system is letting that take precedence. The way to do this is to temporarily uncheck the “Include default CLIA on all claims” under Admin -> Location -> Preferences. Remember to save on this screen:

You can always change it back afterwards. This setting is used to just include the CLIA number on every claim. 

You could instead drive the inclusion of the CLIA number by CPT code from Admin -> Encounter Related Lists -> CPT Code List

For example, for lab code 87880, if this is on any claim, the system will pull in the CLIA number for that claim.