How to Add Form Key in Magento 2

Cross-site request forgery in Magento 2 can be avoided by adding a form key to the Phtml code.

According to Wikipedia, cross-site request forgery results in
"An attacker deceives an innocent end-user into sending a web request that they did not intend. This could result in actions being taken on the website, such as unintentional client or server data leaking, session state modification, or account manipulation.

When you add a form key to Magento 2, you protect your website from spammers trying to post to your forms from other websites pretending to be you!

By putting the solution into practice, Magento will be instructed to look for a layout block named "formkey," output it and store it for the duration of a user session.

Visit here for a programmatical solution.
https://meetanshi.com/blog/add-form-key-in-magento-2/

In this post I will make sense of how for add structure key in phtml record. Add underneath code bit in Block class.