Link juice is a term commonly used in SEO circles to describe the authority that is passed from one site to another through a link. If you can get backlinks from reputable sites, their power spreads to your site making you look better in the eyes of the search engines. This helps your website rank higher as it indicates that you have content that appeals to other people. A backlink serves as a virtual vote of confidence and the link juice from that is a bit like a good review.
There are a few rules around backlinks that you need to be aware of. The most important is to never buy backlinks. There are black hat SEOs out there (dodgy!) who sell links to their clients through private blog networks (PBN). There is initial link juice but it's not quality and it won't last, and when search engines establish your backlinks come from PBNs, your site can get banned and never appear in results pages again. We think you’ll agree that this is not good!
The best way to get backlinks is to create awesome content that people want to read and share. When you have relevant sharable content then you will start getting backlinks with some serious link juice.