Where is my iPhone 6s clipboard?

There is no clipboard on the iPhone.

If you want to copy a hyperlink or text, please highlight it first and then click Copy and Paste in Note, Email, Pages etc.

In this case, the term copy to clipboard is used to indicate that what you want to copy (a hyperlink or text) is remembered by the iPhone's memory until you paste it somewhere.

If you've pasted that link somewhere in the past, you won't be able to access it anymore.

The Clipboard does not store any history.

See also the following Apple articles:

Select, cut, copy, and paste text on iPhone

Select, cut, copy, and paste text on iPhone – Apple Support (UK)

Use Universal Clipboard to copy and paste between your Apple devices

Use Universal Clipboard to copy and paste between your Apple devices - Apple Support

Select, cut, copy, and paste text on iPad

Select, cut, copy, and paste text on iPad – Apple Support (UK)

See this Apple articles below: 

Shortcuts User Guide -> Shortcuts User Guide - Apple Support (IE)

Intro to Shortcuts on iPhone and iPad -> Intro to Shortcuts on iPhone and iPad – Apple Support (UK)

Shortcuts app -> https://apps.apple.com/us/app/shortcuts/id915249334

• Requires iOS 12.0 or later.

iPhone 6s

If it is an iPhone 6S, you can update your iPhone to iOS 15.7.2.