you should create a lead in CRM when the "Ask offer" form is fillup.

the way to do with Odoo Website App is, from Menu "Customize" > "Add Features", then select to install Contact Form" (technical name webiste_crm) module. this will enable a "contact us" form on the website, it generate leads from a contact form.  Whenever a customer fills up, it will appear as Lead in CRM apps. 

Moreover, advanced way if you have an e-Commerce App enabled at the backend of the website, you can let the customer pick up products they want and this will link to create a quotation draft. Sales can  fill/correct price and terms, then send the quotation to the customer. This needs a bit of customization, as odoo default is for the shopping cart.