I downloaded postgresql installer version 11 from official website for windows. when i enter psql and try to create database , database doesn't get created but it is creating by pgadmin4 with no problem

I downloaded postgresql installer version 11 from official website for windows. when i enter psql and try to create database , database doesn't get created but it is creating by pgadmin4 with no problem

You are missing a semi-colon at the end of the line. You need to run:
CREATE DATABASE demo;
you miss semicolon on the end of command.
you should to write CREATE DATABASE demo;
psql by default allows multilines statements, so any statement should be finished by special character and it is semicolon ;