After every reboot Is there any solution to open standby pbd in read only mode on active dataguard ?

Is there any solution to open physical standby pbd in read only mode on active dataguard ?? 

It comes up in MOUNTED mode after server or database restart.

Database version: 19c

Database role: physical standby

OS Type and version:-Red Hat Enterprise Linux Server 7.9

Connected to:

Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production

Version 19.15.0.0.0

SQL> show pdbs

  CON_ID CON_NAME            OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

     2 PDB$SEED            READ ONLY NO

     3 P1MSPORT            READ ONLY NO

SQL> col NAME for a30

SQL> select inst_id, name, open_mode from gv$pdbs;

  INST_ID NAME              OPEN_MODE

---------- ------------------------------ ----------