Title tag
Meta Description
Quality Content
Sitemap
URL Structure
Headers tag
Internal linking
Robots.txt
Update Content Regularly

Yes, its all are important for onpage seo techniques.

In On Page Optimization,Such Factors Are More Important such Are,
Duplicate Content
Website Loading Time
SiteMap
Robots.txt File

On-page factors would include aspects like sitemap, keyword optimization, URL structure, robots.txt file, and a lot of other elements. Meta Tag analysis is also an important aspect for on-page optimization. They are basically all those aspects of your website that you need to take care of so as to optimize the site for search engines.

Title Tag
Meta Description tag
Image with Alt Tag
Quality Content
Sitemap
Robots.txt file
Website Loading Time
Landing Page Optimization...

The Important Factors of ON-page are :
Content of Page
Title Tag
URL
Image alt text
An Ideally Optimized Web Page

Keyword in the title tag.
Keyword in meta description tag.
Keyword in H1 tag.
Using keywords in the pages copy.
The length of the content.
Duplicate content.
Canonical tag.
Image Optimization.

Content
Meta Title
Meta Description
URL
Image alt text
Page Load Speed

Quality Content
Title tag
Meta Description
Sitemap
URL Structure
Internal linking
Image Optimization
Robots.txt
Headers tag
Update Content Regularly