hugo/docs/content/en/functions/urlquery.md

title	description	categories	menu	keywords	signature	relatedfuncs
urlquery	Returns the escaped value of the textual representation of its arguments in a form suitable for embedding in a URL query.	functions	docs parent functions	urls	urlquery INPUT [INPUT]...

This template code:

{{ $u := urlquery "https://" "example.com" | safeURL }}
<a href="https://example.org?url={{ $u }}">Link</a>

Is rendered to:

<a href="https://example.org?url=https%3A%2F%2Fexample.com">Link</a>