hello and thanks for you answer, but 

after developer mode activation I go to website, - configuration and I cannot find templates but i have:

Paramètres

Sites web

 Applications

Redirection

Menus

Ecommerce

etc...

Hi Daniel,

The portal signup form isn’t a normal “form view” that you’ll see in Studio — it comes from a QWeb template in the auth_signup / website modules. The one you’re looking for is usually:

• auth_signup.login (for login + signup screen)
• website_sign_up (in recent versions)

To customize it:

1. Activate Developer Mode.
2. Go to Website → Configuration → Templates.
3. Search for auth_signup.login (or website_sign_up).
4. Duplicate it into your custom module (or edit via Studio/Website Editor) and add the extra fields you already created on res.partner.
5. In your controller, make sure those fields are written back to the partner record when the form is submitted.

So, you won’t find it in “Views” (like form/tree views) — it’s a Website QWeb template.

Hope this helps!