If you want your knowledge base to be indexed by search engines, go to Knowledge Base → Settings → Access Control and enable the "Allow indexing" toggle on that page.
NOTE
If the 'allow indexing' is disabled, your knowledge base articles won't be crawled by search engines and will not appear in search results.

"Public on web" toggle - when disabled, hides the knowledge base website, allowing to access it through te chat widget only.
SEO settings
After you turn on the indexing option, you can specify all the SEO data you need for your knowledge base main page — its meta description and target keywords.
Also, if you want to be able to track your knowledge base traffic in Google Analytics, copy your Google Analytics ID and paste it to the corresponding field in the Knowledge Base advanced settings.
Social media settings
You can also specify the social title and description for your knowledge base as well as upload a custom image for social media.
In order to solve this, go to @webpagebot, click "Start," and enter the URL of your knowledge base.
After hitting Enter, the image will be refreshed in all Telegram chats, including past ones.