Main entry in the category how to do?

Question

Search Engine Optimization

Hello!
The question is, I noticed that on a wordpress blog, if you put several categories in a post, then wordpress assigns the main category with the smallest id,

but how to force the selection of the main category for the post?

Answer 1

out of the box,
look for plugins, maybe there

Answer 2

To get the same look (classic editor) of an edited Post in Wordpress, you need to disable Gutenberg. This can be done using plugins.
In the Classic Editor, the reassignment of Headings "Main/Secondary" looks like this:

At the same time, keep in mind that, depending on the URL generation rule, the Post URL structure may or may NOT change when the "Main" heading is redefined.
1st URL type: domen.ru/rubrika-1/nazvanie-statiy
2nd URL type: domen.ru/nazvanie-statiy
For example, we have two rubrics "rubrika-1" and "rubrika-2"
If the Post URL are formed with nesting according to the 1st type (see above), then:

• making "Main" "rubrika-1" we get the URL: domen.ru/rubrika-1/nazvanie-statiy.
  
• making "Main" "rubrika-2", we get the URL: domen.ru/rubrika-2/nazvanie-statiy.
  

As a result : each time you reassign the "Main" heading, you change the URL of the Post, with all the consequences - the loss of positions, trust and external links, if any.
If Post URLs are formed with nesting of the 2nd type (see above), then changing the "Main" category will NOT affect the URL, i.e. it will remain as it was domen.ru/nazvanie-statiy.