Getting high-quality backlinks is crucial for improving your website's search engine ranking.

Here are some websites with high Domain Authority (DA) that you can use to get free backlinks:

Wikipedia

One of the most authoritative websites on the internet with a DA of 100.

Medium

A popular online publishing platform with a DA of 95.

Quora

A question and answer website with a DA of 92.

Scoop.it

A content curation website with a DA of 89.

LinkedIn

A professional networking site with a DA of 95.

Tumblr

A microblogging and social networking site with a DA of 92.

Blogger

A free blogging platform with a DA of 95.

Reddit

A social news aggregation and discussion site with a DA of 90.

Issuu

A digital publishing platform with a DA of 92.

Slideshare

A presentation-sharing site with a DA of 94.

It's important to note that not all websites will allow you to post backlinks, and it's also important to avoid spammy or low-quality backlinks, as these can actually harm your website's ranking.

The key is to focus on building high-quality, relevant, and authoritative backlinks from reputable websites in your niche.