Odoo addons

To add modules:

first create a location of where the modules will be stored. Odoo does not make one by default. You will need to create your own path.

/home/some/location/you/want/extra-addons

Edit the files: 

/etc/odoo/odoo.conf

Add path in that file: Any spot in the file will do. 

addons_path = /home/some/location/you/want/extra-addons

Restart Odoo to make sure it is working

sudo systemctl restart odoo