An external link is a standard web link targeting for example a website. For example, https://en.wikipedia.org/wiki/South_China_Sea is an external link to a Wikipedia page.

To create a link without a custom text:

To create a link with a custom text:

Once a link is inserted:

You can follow external link by either double clicking (will open new tab/window) it or right clicking on them and choosing "Open in new tab".