Redirects can be created by adding a new page with the page type "Redirect". The redirect may be to a page on your site, or on another domain. 

For example, if you'd like to redirect to your old domain, create a new Page called "Old" and put in as the Redirect. You may want to hide this page under a "Hidden Parent" page, with the visibility set to admins only, so that it doesn't clutter your site navigation.

You can bulk import redirects in Admin > Settings > Import > Redirects.