blog
Sure, if you're asking and they say "great web page" and link to it.

article
See above

ppt and pdf
Hell no and no.

social bookmarking
Oh hell no.

or something else
This. Just make things that people will want to link to then do a link beg campaign.

Good luck!

Roger

Thank you Roger for helping me out, it is really helpful.

From what I have noticed there is no such thing as backlink strategy. You just need to have big sites on which you can build backlinks and get them indexed they are good enough.
But the main concern is that you only need backlinks or you also need relevant traffic with those backlinks.

So how can I find these websites to get relevant traffic with that kind of backlinks?

A strategy helps bring focus and a plan.

To state the obvious, the easiest and simplest way is to research relevant sites in the SERPs. The second obvious way is to promote the information through publications, etc.
There is no silver bullet.

Building a backlink strategy involves creating a plan to acquire high-quality inbound links to your website, which can boost your site's authority and improve search engine rankings.

To build a successful backlink strategy, focus on creating valuable and shareable content, such as blog posts, infographics, or research reports, that others will want to link to.
Engage in guest blogging on reputable sites within your industry, ensuring to include a backlink to your site in your author bio.
Additionally, leverage social media to share your content widely, increasing the chances of earning natural backlinks.
Finally, monitor your backlinks using tools like Google Search Console or Ahrefs to assess their quality and identify opportunities for improvement.