Role of link Juice
Link juice is a Search Engine ranking factor just like another factor .link juice is passing authority from a trusted page to another page .link which is trustworthy when they share their link to another page then its ranking start improving in search engine result page (SERP).
Only sharing link is not enough there are many factors which you should keep in mink while sharing link :
Share link With Common Interest
Always remember that share link with site of the same serving purpose. For example, if your site related to finance hence share a link to the site of finance not of any other field.
It has some authority
Exchange juice links from a site that has gained some authority over the period of time.
link Must Be Follow
Follow link passes their authority whereas no follow passes the signal to the crawler that link needs to be ignored.
location of link
Some of the research says that the link that is located to the sidebar and footer doesn’t follow much authority .link which is located to the body passes more trust.
Amount Of link On The Page: If your page has hundred and thousand of links. Then it doesn’t give muck link juice. So don't spam transfer link juice if you found it normal since google is far intelligent than our tricks.it blacklisted whose intention was not right.
Is the link crawlable:
if the page blocks the crawler via robots.txt file, then the link doesn’t pass much link juice.
As we see there are many factors to improve the ranking of a site link juice is one of them. If anyone asks a question from you what is the one tip for good vegetables then you would get confused because there is no one factor which makes good vegetables the same as that there is not a single factor which enhances the ranking of your site one factor.some tool to check the link juice is Moz, Ahref, etc.