There are reasons to clear your browser's cookies too, but we're going to focus on the cache here. This is how to do the job no matter what browser you're using.

To clear the cache on your iPad, open Safari > tap on the Show Sidebar icon on the top-left > click on the History icon > and tap Clear. Both of these icons are highlighted in the screenshot above.

Cache and cookies are meant to improve users' experience with their phones, but not clearing them often can have negative consequences on users' experience, such as slowness.