How to remove a canonical and redirection from a page ?

Hello,

I work on the website : http://www.grim-occasion.com and we have RankMath SEO plugin.

Some of my pages can’t be indexed on Google because a canonical URL is set on them.

For example, on the page : https://www.grim-occasion.com/voitures/ford/ there is a canonical URL for this page https://www.grim-occasion.com/voitures/

To improve our SEO, we have written texts on several pages but the can’t be recognized by Google because of the canonical URL.

How can we manually remove the canonical when a text is written on a page ?

Best regards,

Caroline