Create a read only account

Script to Create Read-Only user:

CREATE ROLE Read_Only_User WITH LOGIN PASSWORD 'Test1234' 
NOSUPERUSER INHERIT NOCREATEDB NOCREATEROLE NOREPLICATION VALID UNTIL 'infinity';

Assign permission to this read only user:

GRANT CONNECT ON DATABASE YourDatabaseName TO Read_Only_User;
GRANT USAGE ON SCHEMA public TO Read_Only_User;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO Read_Only_User;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO Read_Only_User;