Fill in the title, description, URL and image, choose the content type and the card style, and copy the meta tags that decide how your link looks on LinkedIn, Facebook, X and Slack.
Enter the title and description you want shown in the preview, the page URL and the image URL, ideally 1200 by 630 pixels. Pick the content type, add the site name, and choose a Twitter card: summary_large_image for a big picture or summary for a small one. Press Generate and paste the tags into the head of the page. Then paste the URL into a LinkedIn or Slack message to check the preview.
When someone shares your link, the platform builds the preview from Open Graph tags. Without them it guesses, and the guess is usually a cropped logo, the wrong text or nothing at all, which is why the same article gets many times the clicks with a proper card. The tags take a minute per page and they do not depend on the platform, so one set works everywhere.
1200 by 630 pixels, under 1 MB, in JPG or PNG. That ratio works on Facebook, LinkedIn, X and most chat apps without cropping.
Platforms cache previews. Use the Facebook Sharing Debugger, the LinkedIn Post Inspector or X's card validator to refresh them after you change the tags.
X reads Open Graph tags as a fallback, but twitter:card is what sets the large image layout, so include both. This tool outputs the pair.