If a user needs to create an account on a Drupal site, they go to the user registration page at "/user/register". This page is the registration form on a Drupal site. You can customize it by adding or removing fields.
With the Toolbar Menu module, you can add as many menus as you need to the toolbar of your Drupal installation. By default, a Drupal 8 installation has 3 menu links in its toolbar.
The Linkit module allow site editors to work in a more comfortable way when linking to internal entities (i.e. content, users, taxonomy terms, files, comments, etc.) and when linking to external content as well.
As a web developer, you probably build your sites first in a local environment (aka localhost), then you commit all your changes to a staging server (i.e.
If you're planning to use Bootstrap on your Drupal 8 site, the first obvious thing to do is download and set up the Bootstrap theme. Then, during the site building process, there will come the point where you need to create a few layouts.