There is much information around that rightly states that moving from http:// to https:// will improve your SEO and rank you higher on Google. However, please be warned that unless done correctly, your rankings will almost certainly drop, initially at least, if making this change on an established site…
The best approach to this change is to regard it as a full project and allocate sufficient time and resource, and if you find this article and the accompanying checklists confusing, then enlist expert help. If you don’t have the time to make this change in a thought-through detailed way, or the money to hire an expert to do it for you, then our advice is certainly not to do it at all – you’ll not get the results you want/expect unless you spend time on getting it right.
There is a wealth of well-written articles on this subject, so I don’t feel the need to repeat it all here. For a comprehensive overview of why you should change from http to https and then a detailed checklist of how to do it, see: https://www.keycdn.com/blog/http-to-https
If you are with our highly recommended hosting providers Siteground, then they have a handy WordPress plugin called ‘SuperCacher‘ which includes a tool to ‘force HTTPS’ – useful as a quick way to eliminate those mixed content warnings that can scare visitors away from your website. But there are SEO advantages in doing a thorough and painstaking update of all your website code manually, maybe also using a tool like ‘Search Replace DB’ to speed up parts of this process. Please be aware that ‘Search Replace DB‘ is a powerful tool only to be used by experienced developers who are aware of the damage it could do to your website if used incorrectly.