Hi,

To achieve your requirement, you can create an automation rule.

Go to Settings and enable Developer Mode, and in the Technical Menu under Automation, you can select the Automation Rule menu. If the menu doesn't exist, you have to activate the base_automation module from the Apps menu and create the rule as per below. 

From the Action To Do Tab, add an action to create the opportunity.

Hope it helps

done but it's not working....

thanks but I don't know python... can you tell me if there is a way without writing code or can you describe everything step by step?  code included .☺.?

Hello Enzo, 

Yes, you can create with the help of automation rules. 

Just like you need to create one rule there you need to configure it like any record is created in sales from the website at the same time you need to create a record in CRM as well. 

For more information, you can find a similar question related to helpdesk module. 

Ref. https://mkberp.in/r/oVH

Thanks