Hello,

For ubuntu using terminal:

if you are using ubuntu then you have to go terminal, into terminal type 'sudo su postgres', then psql 'Target Database'

For ubuntu using pgadmin:

open pgadmin software and into that software select your target database then at top tap SQL button for run your queries

For Windows:

open pgadmin software then select your database and tap SQL which is at top of the software.

Thanks & Regards

Ankit Vaghela