How should I write multiple data returned from a column separated by commas next to each other?

Hi,

I actually have a pretty simple little query. More than one data is returning from this column and I want to write it on the same line separated by commas.

SELECT YY4.PEI_INFORMATION2

 FROM (SELECT *

     FROM PER_PEOPLE_EXTRA_INFO_F PPEI

     WHERE   PPEI.INFORMATION_TYPE = 'Onboarding'

        AND SYSDATE < PPEI.EFFECTIVE_END_DATE

        AND PEI_INFORMATION1 = 'APPS') yy4,

    per_all_people_f papf

 WHERE YY4.PERSON_ID(+) = papf.person_id

I will join to my main query with 'papf.person_id'.

Thanks