This will helpful:

Hi,

The "Customize Login Page Style" app on the Odoo apps store . We can configure the login page according to our needs. For this a new option is added in the general settings and based on that we can change the alignment of login to the left, right, middle or default. Also, there is an option to change the background of login page as image, url or color. Here is link to the app: https://apps.odoo.com/apps/modules/16.0/web_login_styles/

Hope it helps