On your remote client create a tnsnames.ora file and set TNS_ADMIN to the directory where you created it.
You can copy the database entry tnsnames.ora into the client tnsnames.ora. It will look something like:
XEPDB1 = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = your_db_server)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = xepdb1) ) )
As you have displayed no errors, it is assumed you have sqlplus already on your remote client machine, if not you can download instantclient: basic or basiclikte, along with sqlplus from here: