You delete cookies and cached files in your browser settings. Your browser is the program you use to browse the internet (for example, Firefox, Safari or Google Chrome). We do not recommend that you use Internet Explorer or Edge. It is better if you download either Google Chrome or Firefox or use Safari on Mac.
The approach on how to delete cookies and cache varies a bit, depending on which browser you use.
You can follow these guides on how to delete cookies:
Safari on Mac: https://support.apple.com/en-gb/guide/safari/sfri11471/mac
Safari on iPhone/iPad: https://support.apple.com/en-gb/HT201265