Relational database: Shell script is not running in local host

I downloaded PostgreSQL
When I enter psql --version in Powershell (Windows), it says
psql (PostgreSQL) 15.3
Basically, psql is installed.

universe.sh file:

PSQL="psql --password --expanded --host=localhost --username=postgres --dbname=postgres --tuples-only -c"
echo $($PSQL "SELECT * FROM sample")

When I run this file using Bash universe.sh, terminal throws an error:
universe.sh: line 2: psql: command not found

Why is this happening even though psql is installed?