You can find the FONT keyword under the parameters of the field.
After taking “Shift + F11″ at corresponding field, It will look like,

                           Work with Field Keywords                            
                                                                               
Field  . . . . . . . . :   TSTFLD02      Record format  . . . . :   RCD001     
                                                                               
Type options, press Enter.                                                     
  2=Specify   4=Remove                                                         
                                                                               
Opt     Keyword            Opt     Keyword            Opt     Keyword          
        ALIAS                      DFT                        PRTQLTY          
        BARCODE                    DLTEDT                     REFFLD           
        BLKFOLD                    EDTCDE                     SKIPA            
        CDEFNT                     EDTWRD                     SKIPB            
        CHRID                      FLTFIXDEC                  SPACEA           
        CHRSIZ                     FLTPCN                     SPACEB           
        COLOR                      FNTCHRSET                  TEXT             
        CPI                     >  FONT                       TIME             
        CVTDTA                     HIGHLIGHT                  TIMFMT           
        DATE                       INDTXT                     TIMSEP           
        DATFMT                     MSGCON                     TRNSPY           
        DATSEP                     PAGNBR                     UNDERLINE        

If you cant be able to get the same(FONT) in the attributes list, You can use the FONT keyword directly by opening the DDS source of printer file at the corresponding field.

The above case is only if you like to change the font of particular field.
if you would like to increase the font of Complete Printer file. Then you can change the FONT while compiling printer file.

                          Create Printer File (CRTPRTF)                         
                                                                                
 Type choices, press Enter.                                                     
                                                                                
 Print quality  . . . . . . . . . PRTQLTY        *STD                           
 Form feed  . . . . . . . . . . . FORMFEED       *DEVD                          
 Source drawer  . . . . . . . . . DRAWER         1                              
 Output bin . . . . . . . . . . . OUTBIN         *DEVD                          
 Font:                            FONT                                          
   Identifier . . . . . . . . . .                *CPI                           
   Point size . . . . . . . . . .                                               

CRTPRTF and F10(Additional Parameters), FONT will be set to *CPI by default. You can change the Font Size based on your Requirement.

Pradeep.

Am using RLU only and in Report format keyword, there is no format as you mentioned or the keyword FONT. And I saw CPI only which is having 10 or 15 only…
Please provide more clarification how to solve this..

Jayashree V.

http://publib.boulder.ibm.com/html/as400/v4r5/ic2979/info/db2/rbafpmst634.htm

If you just need to increase the size, You can use it like this.

FONT(font-identifier )

The valid values for this parameter are 0.1 through 999.9.

Pradeep.

Worldsoft Report Design

What is the tool you are using for Report design.
If you are using RLU(Or designing by using DDS), You can use FONT Keyword for mentioning the Font type at Field level.
The format of this keyword is

FONT(font-identifier | &font-identifier-field
    [(*POINTSIZE height-value | &height-value-field
    width-value | &width-value-field)])

You can find little more info and sample code using below link.

Pradeep.