Hello Alejandro Velasquez, 

Dynamic Default value is Not Support by odoo Studio

If you Want to current Date then we have one more Idea.

You will Create the Fields As Compute

Readonly = False

Stored = True

Dependencies = partner_id

# Please Make Sure in Dependencies it was use every time when you Filling the Data so most probebly use required Fields

Compute

=======

for record in self:

record ['x_studio_date_field_name'] = datetime.datetime.now ()

So in above method when the Customer will change the it will compute and set the Today Date or Datetime.

Thanks ..

For more information Contact us:- https: //kanakinfosystems.com/odoo-development-services