You can create an ads.txt file in your WordPress website root directory by following these steps.

1. Go to your WordPress website Dashboard.
2. Click on Plugins in the WordPress menu.
3. Click the Add New Plugin button at the top of the Plugins page.
4. Type Filester in the Search Plugins area at the top right corner. This will search the plugin and bring in the results of File Manager Pro -Filester, an advanced File Manager and code editor.
5. Click on the Install Now button on the filester plugin.
6. Once the plugin is installed, click on the Activate button. Your filester plugin will get activated on your WordPress website, and a new menu option File Managerwill appear in your WordPress website dashboard menu.
7. Click on the File Manager option on the menu. This will open the Filester plugin page, and in that, you will notice the public_html folder in the left menu as a main option under other folders like .private, wp-admin, wp-content, and wp-includes and on the right side, you will see these folders and other files like .htaccess, index.php, robots.txt, and others.
8. Right-click on the right side, where all the folders and files appear, and a dialog will appear. Select, and a new continuous dialog will appear next to the first dialog box. Select TXT: Plain text. This will create a NewFile.txt in your root directory.
9. Rename the NewFile.txt to ads.txt during its creation or right-click on the NewFile.txt and select the option Rename on the appearing dialog box.
10. Once the file is renamed to ads.txt, Right-click on the ads.txt file and open the file in edit mode by selecting the option Edit File, and then TextArea editor, the ads.txt will be opened in edit mode.
11. Now, you can copy the default ads.txt code mentioned in point 5 by visiting the Ads.txt Guide page.
12. For your convenience, I am writing that code here as well. Here, pub-0000000000000000 is your publisher ID. google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0
13. Replace pub-0000000000000000 with your publisher ID, Therefore to find your publisher ID then go to your AdSense account. Click on the Account option on the left menu. The Account option will get expanded and you will see the Settings option under it, click on that, and the Setting option will further expand and you will see the Account Information option under it. Click on that option and the first thing you will see next to the menu options is your publisher-ID.
14. Once the code is pasted to the ads.txt file. Click on Save. Now your ads.txt file is ready and the next time when Google bot crawls your website it will find the ads.txt file on your website and will change your ads.txt status.
15. You can also verify the ads.txt presence on your website by just adding /ads.txt to your website URL on the browser and pressing enter. You will see the code that you added to the ads.txt file.https://mywebsitename.com/ads.txt

You can follow the below steps to update the last modification date for all posts, questions, and pages on your WordPress site sitemap.xml at once.

Using SQL Query for bulk update:

You can use SQL queries to update the post_modified and post_modified_gmt fields in the WordPress database.

• Please back up your database before making any changes using SQL query.
• Access your WordPress database from your hosting provider site using a tool like phpMyAdmin.
• Run the following SQL query to update the modification date to the current date and time for all posts, pages, and questions on your site.
  UPDATE wp_posts
SET post_modified = NOW(),
post_modified_gmt = UTC_TIMESTAMP()
WHERE post_type in ('post', 'page','question')
AND post_status = 'publish';This SQL query updates the post_modified date, which Yoast uses to generate the tag in your sitemap.

I have enabled Prevent crawling of internal site search URL settings for the Advanced Crawl optimization; however, I cannot see the added directives to my robots.txt file.

Enabling the settings Prevent crawling of internal site search URLs
Add a disallow rule to my robots.txt file to prevent the crawling of URLs like ?s=, /search/ and /page/*/?s=.”, this should add the following directives in the robots.txt file:

Disallow: /?s=
Disallow: /page/*/?s=
Disallow: /search/

However, I observed that the crawl directives would not be added to my default robots.txt file. Instead, it has already been added to the static robots.txt file here: https://example.com/?robots=1.

the code added to static robots.txt which is the Yoast output.

# START YOAST BLOCK
# ---------------------------
User-agent: *
Disallow: /?s=
Disallow: /page/*/?s=
Disallow: /search/
Disallow: /wp-json/
Disallow: /?rest_route=

Sitemap: https://example.com/sitemap_index.xml
# ---------------------------
# END YOAST BLOCK

robots.txt file is placed in the root directory of your WordPress site that provides instructions to the web crawler as to which part of the site is crawled or not.

For example, you can always block certain directories, web pages, or other resources on your website from getting indexed by search engines like Google or Bing.

You can see the contents of the robots.txt file by going to the page https://example.com/robots.txt.

On the other hand, meta robots tag ?robots=1 is used at a page level to control whether individual pages should be indexed or followed.

When you visit a page on your website with the ?robots=1 query parameter, then you can check the robots meta tags settings for that specific page.

You can see how indexing instructions like index, noindex, follow, and nofollow are applied to your specific page.