Hi to all, is’t possible to use the same header in all the page, and not change singluar element in every page when needed ?
thanks in advance
Not sure to fully understand the question, but as long as you have defined a header (and by extension, a footer) on your/a theme master page, you can use both elements in any other template that you will create. You just have to fill the Master page settings from the page settings.
Wrong idea, header and footer (templates) should not be handled with reusable template parts but with master pages (you can have as many master pages as you want/need).
Reminder > header & footer templates are automatically generated when you define the SITE CONTENT. (see template fundamentals here Introduction to the WordPress template structure - Headers, Footers, Site content and Master pages | Pinegrow Web Editor)
IF you don’t DEFINE your SITE CONTENT, (from what I see on your screenshot, this action is not present) Pinegrow will try to guess it for you and will give results that may not suit you completely. You might as well do it yourself, it’s so easy.
Still, you can use reusable template parts anywhere you want, including in the header & footer (templates).
I hope my explanation is clear enough. It’s a mix of WordPress fundamentals and the way they are handled in Pinegrow.
And by the way, more generally, all the sections present in our dedicated WordPress documentation deserve to be actively consulted 
See here: Creating and designing WordPress themes | Pinegrow Web Editor
We also have a very complete FAQ that answers a LOT of questions: