@marimuthu89
Hi, Yoast does not have a way to automate keywords. However, with the meta description if you leave it blank you let Google automate it. Google will then create one it best thinks works with the post/page. With the title, Yoast automatically outputs the title of the post/page as the SEO Title which will appear in Google.
The only way to force Yoast to automate keywords is to develop on the plugin. Unfortunately, there’s a difference between the support we can offer and the level of programming needed to change (core) features of our plugin. Since we don’t want to take the risk that we break your website by suggesting incorrect or incomplete code, we cannot advise you on how to make such changes. And even though we cannot be of any assistance, you’re completely free to change anything in the plugin to better suit your needs.
We highly recommend checking out?our list of Yoast Partners here https://yoast.com/yoast-partners/ in case you are in need of development.
We will also keep this issue open for 2 weeks in case someone from the community can help. Perhaps a developer watching these forums can assist further. After which, we will close in order to keep the overview.