Created Freitag 09 April 2021
A user in PostgreSQL is called a role.
PSQL
<SQL DB>=# \password <User/role name>
SQL
<SQL DB>=# ALTER ROLE <User/role name> WITH PASSWORD '<Password>';
Examples
Change user postgres password to This is @ secure p$$word!.
<SQL DB>=# ALTER ROLE postgres WITH PASSWORD 'This is @ secure p$$word!';