Add widgets by going to Customizer → Widgets.
The footer has four widget areas:
- Footer (Column 1)
- Footer (Column 2)
- Footer (Column 3)
- Footer (Column 4)
You can choose how many columns you want to use by adding widgets to each area. Example: If you add a widget to Column 1 and Column 2 but leave the other two empty, then the footer will have two columns, taking up 1/2 of the width each.
In the example below, all four widget areas are used, so each widget area takes up 1/4 of the width:
There are multiple plugins available to add a newsletter subscription form. Which one you should use depends on which newsletter subscription service you use.
The plugin Contact Form 7 is recommended for the theme. This plugin makes it possible to add contacts forms. There are other plugins that works well together with Contact Form 7.
If you use Mailchimp, you might want to try the plugin MC4WP: Mailchimp for WordPress which works well together with Contact Form 7.