Confusing error about missing left parenthesis in SQL statement

You need to specify a size for the VARCHAR2 data type.

E.g. VARCHAR2(30)

SQL*Plus is looking for the brackets around the VARCHAR2 size definition.

VARCHAR2 is a type that needs a maximum size/length. Try something like...

varchar2(50)

Your missing left parenthesis is the parenthesis that surrounds the size.

CREATE TABLE people(
    id INT NOT NULL PRIMARY KEY,
    name VARCHAR2(50) 
);