Understanding schema and schema password in Oracle APEX 18c XE

When you install Oracle APEX 18.2, and before creating a new application you create an SCHEMA.

A password is given to that schema.

Then you create an admin user and you can create other users.

My understanding is that the SCHEMA is an actual database user which can be used to log into the database.

If I connect as SYS to the PDB where APEX is installed with SQL Developer I can see in "Other Users" my schema user.

However, when I try to connect to database using it it does not work:

So this works fine:

     sqlplus sys/[email protected]:1521/xepdb1 as sysdba

But this (given that my schema is scott and the password is tiger) does not work:

     sqlplus scott/[email protected]:1521/xepdb1

     ERROR:

     ORA-01017: invalid username/password; logon denied

As the schema user is not working, I start to think that I misunderstood what a schema is and what shall be used for.

I have the following questions:

1. Shall the schema created by APEX be available as a database user?

2. Shall I use it when I want to access externaly to APEX (for example, another external progra which needs to interact with APEX application tables). If so, how can I check that the user/schema can be accessed? Could it be a permissions issue?

3. If not, why I am providing a schema password, and how shall I achieve point 2 (accessing the database externaly to interact with APEX application tables)

Thanks