Two important question about seo in my mind

Hi friends

I have two questions in my mind about seo and i hope here you answer them :

1-I write about seo and social media on my blog and i have seen my competitor that rank 1st on my target keywords in his articles he link keywords to site main domain. He post articles in his site and no subdomain. but in his articles he usually link some keywords to site main URL , i want to now it have any effect on SEO ?

2- if I have a web site with fixed content like hosting company or eBook landing page in HTML or php and i create blog in WordPress and post articles in blog section. this will rank whole domain in google or blog part will rank itself ?

I am waiting for your advice

1. Backlinking back to the domain throughout the site sends link juice back to the main page. This focuses on ranking the domain instead of the articles

2. Creating the blog posts and lining back to your website will rank the site with fixed content. The purpose of the blog post is to provide context for the link so Google can see what the post and link is all about.

Tnx for advice Bro