SQL> conn tc/tc@localhost/pdb
Connected.
SQL>
SQL> grant create table to scott identified by tiger;

Grant succeeded.

SQL> alter user scott quota unlimited on users;

User altered.

SQL>
SQL> drop table scott.emp;

Table dropped.

SQL> create table scott.emp(client_name varchar2(30));

Table created.

SQL>
SQL> insert into scott.emp
  2  select trim(column_value) from xmltable('"Larry Ellison","Jeff Bezos","Elon Musk","Vladimir Putin"," "');

5 rows created.

SQL>
SQL> exec DBMS_REDACT.ADD_POLICY( -
>      object_schema         => 'SCOTT', -
>      object_name           => 'emp', -
>      column_name           => 'CLIENT_NAME', -
>      policy_name           => 'client_fio', -
>      function_type       => DBMS_REDACT.REGEXP, -
>      regexp_pattern      => '(\S{3})(\S+)', -
>      regexp_replace_string   => '\1***', -
>      expression            => '1 = 1' -
> )

PL/SQL procedure successfully completed.

SQL>
SQL> col client_name for a16
SQL> col c1 for a16
SQL> col c2 like c1
SQL> col c3 like c1
SQL> create or replace view scott.vw as
  2  select client_name
  3       , nvl(client_name, 'zyzy') c1
  4       , case when client_name='Vla*** Put***' then 'y' else client_name end c2
  5       ,'hi '||client_name c3
  6    from scott.emp;

View created.

SQL>
SQL> grant alter session, create session to tc2 identified by tc2;

Grant succeeded.

SQL>
SQL> grant select on scott.vw to tc2;

Grant succeeded.

SQL> grant select on scott.emp to tc2;

Grant succeeded.

SQL>
SQL> conn tc2/tc2@localhost/pdb
Connected.
SQL>
SQL> alter session set events 'trace[radm]';

Session altered.

SQL> select * from scott.vw;

CLIENT_NAME      C1               C2               C3
---------------- ---------------- ---------------- ----------------
Lar*** Ell***    Lar*** Ell***    Lar*** Ell***    hi Lar*** Ell***
Jef*** Bez***    Jef*** Bez***    Jef*** Bez***    hi Jef*** Bez***
Elo*** Mus***    Elo*** Mus***    Elo*** Mus***    hi Elo*** Mus***
Vla*** Put***    Vla*** Put***    y                hi Vla*** Put***
                 zyzy                              hi