Hi,

You can see the conf file in this path: /odoo/debian/odoo.conf

Or in Github, this link:  https://github.com/odoo/odoo/blob/13.0/debian/odoo.conf

If you didn't spot one config file, you don't want to get confused you can just create a new file in this name in the anywhere as you need, if you are running odoo with pycharm, in the configuration you can specify the path to conf file, if you are running using service specify the configuration file by -c path_to_conf file .

Pycharm Configuration:

Sample Conf File:

[options]
; This is the password that allows database operations:
; admin_passwd = admin
db_host = False
db_port = False
db_user = odoo
db_password = False
;addons_path = /usr/lib/python3/dist-packages/odoo/addons

Thanks