2/ Can’t change this too, i want to remove the “Thème par Colorlib. Propulsé par WordPress”
You can remove this by using the attached child theme of Sparkling theme that contains some custom code.
3/ Where i can find the menu to add our social link for the widget … ?
To add social links for the widget you have to create social icons menu as described below.
Create a menu like any other menu in the admin area of your site under Appearance -> Menus .
Use the correct urls in the menu items, so for twitter it must be twitter.com for facebook it must be facebook.com. Otherwise URLs won’t get recognized and you will get squares without icons.
Set theme location for this menu as “Social Links”
Can we change the typography from the title of those articles ?
I am not sure whether you are talking about the single post title or post titles on the posts listings page and whether you want to change font family so please advise.