Welcome to Odoo! Setting the number of decimal places after the comma in Odoo 18.0 is quite straightforward. Here’s how you can do it:

1. Activate Developer Mode:
   • Log in to your Odoo instance.
   • Activate developer mode by adding ?debug=1 to the URL or by selecting it from the user menu.
2. Navigate to Decimal Accuracy Settings:
   • Go to Settings.
   • Under the Technical menu, find Database Structure and then Decimal Accuracy.
3. Adjust Decimal Accuracy:
   • Here, you can see a list of different fields and their current decimal accuracy settings.
   • Find the field you want to adjust (e.g., Product Price, Tax, etc.).
   • Click on the field and set the desired number of decimal places.
4. Save Changes:
   • After adjusting the settings, make sure to save your changes.

FYI geert I found that copilot together with this forum where a great help when I just started with odoo. :)