A 301 redirect or permanent redirect is the best way to tell Google or any other search engine for that matter that you have moved pages in your site or across domains.
The .htaccess method in the root of your domain is for those that have Apache
This tells Google to permanently change the link it has for a current page to a new location. i.e. if I had an old About Us page located in https://www.handshake.co.za/aboutus.htm and decide to move it or implement a cms and now the page is here https://www.handshake.co.za/about-us/
There are some useful tools to help make this process as simple as possible, here are some I found
Apache .htaccess rules
http://httpd.apache.org/docs/2.0/misc/rewriteguide.html
Look under “Content Handling” – “From Old to New (extern)”
Tool to assist in generating .htaccess files
http://seo-website-designer.com/HtAccess-301-Redirect-Generator#heading-ToolResult