What seed keyword should I use ?

There are several types of seed keywords you can use : broad or narrow ones.

A broad seed keyword like car will generate more general keyword ideas and can help you better understand the topics related to your business.

These keyword ideas are usually more competitive.

A narrow one like best car for will provide more targeted, long-tail, keyword ideas that might be more interesting as you'll get a majority of high-intent keywords.

These keywords ideas are usually less competitive.

When using a wildcard (*), in the seed keyword, keyword ideas will match a specific structure.

For example, best car for * will only provide keywords that are of type "best car for something".

how to * car => "how to something car".

I recommend playing around with the more specific and wildcard searches to generate some highly relevant keyword ideas.

Example of keyword ideas per type of search :

car : 2913 (broad search)

best car for : 1374 (more specific search)

best car for * : 339 keyword ideas (highly targeted search)