Hi, SEO is a best technique to increase the visibility of a website or web page. First step (Link Building) has to be followed to get power to keyword to get on higher position. But when we are doing that & checked after few days search engine didn't Crawl or Indexed link. Not getting a proper solution why it happening. If you have better answer than please provide a solution.
In order to protect its user experience, google releases new updates. These updates are meant to penalize sites that do not meet up with the required elements. Like googles latest update rankbrain that will rank post higher due to how interested the readers are to this post. So you want to make sure you have not been hit by any of google updates. You want to check all of them and see when and why they will penalize a site and fix the situation before all your link building process will go for vain.
Generally, Google takes 5-7 days or sometimes longer to cache and index a link, so you could wait for a few more days. If still, you link is not getting cache & index you can check the website source code (Where you have created Link) if there is any Noindex tag implement over there.