Relevant policy: Wookieepedia:Layout Guide#External links
If you want to link to a site outside of Wookieepedia, it should almost always go under an "External links" heading at the end of an article. Avoid using an external link when it's possible to accomplish the same thing with an internal link to a Wookieepedia article.
The best type of link for most situations includes a description after the address. This description appears as the title of the link (e.g. the official Star Wars site). To create a link like this, just type a link and description, separated by a space and enclosed in single square brackets:
[https://www.starwars.com/ Official ''Star Wars'' site]
When placed under the "External links" heading, the links should be listed in bullet-point format:
==External links==
*[https://www.google.com/ Google Search]
Other ways to link
There are two other ways to create an external link.
Enclosing the link in single square brackets without providing a description…
[https://www.google.com/]
…will display the link as a number in brackets, like this: [1]. This format is mostly used for citing sources within an article. It looks like a footnote, so it's best to use it only as such (for example, following a direct quote or a statement which requires a source). Avoid this usage: "According to [2], the last full moon of the second millennium occurred on December 11, 1999." Do this instead: "The last full moon of the second millennium occurred on December 11, 1999. [3]"
Finally, you may simply type in the full URL for the page you wish to link to:
The wiki will automatically treat this text as a link (as has been done with the URL above) and will display the raw web address, including the "http://" part. It is recommended that you avoid this format entirely, as raw URLs are ugly and often give no clue to what the site actually is. For better info on external links, see Wookieepedia:Sourcing.