Google has just changed up the link building guidelines.

When you state about backlinks, the thought that quickly strikes is no-follow links & do-follow links that point to your site.

One of the most prominent ways to produce back links is guest posts. However, there are very fewer efforts taken to craft content that can actually be submitted organically & approved. Paying to get guest posts included are gaining traction. Even if you do so, they should be no-follow as per Google. Tactics like disbursing to get your articles featured is a big no-no because they manipulate rankings. Doing so can penalize your site or altogether ban it from Google.