How to set only one save button for a page with Editable Fields by Views?
You can use Editable views module. It uses one save button for all fields in a view.
Editable Views:

Editable Views lets you create Views where the fields can be edited. Fields show both the current value and a form to edit it. A 'Save' button allows saving of all the entities shown in the View.
Editable fields can be added on the base entity as well as on entities brought into the View by a relationship. Other, non-editable fields may be added to the View, in which case they function normally.
Currently, the following Views fields can be edited:

All FieldAPI fields
Node title