Each interview has a deadline date. If you intend to complete the interview then you must complete the interview before this date. You will not be able to access the invitation link once the deadline date has passed.
If you require a deadline extension then you should request this by replying to your invitation email specifying the date when you will be able to complete the interview as well as your reason.
Please note that extension requests are subject to approval by the hiring company.
If your extension request is approved then you will receive an email like this:
If you do not complete your interview in the given timeframe then you will receive an email asking you to specify whether you are still interested in the opportunity. Your response will be communicated to the hiring company so they can decide what action to take.
Here is an example of that email: