In the list of your applications, only those with the status "Commenced" (applications you started but never sent) or "Deleted" (applications that have been deleted/removed from the employer's account) can be removed. Only these have a trash can icon, and you use this icon to delete them!

You can see these by going to your applications:

In the list of your applications, you can see which ones you can delete:

Applications you have sent (those with the status "Applied") cannot be removed from the list/account until they have been deleted from the employer's account. This is done in accordance with GDPR, and usually occurs 24-36 months after the recruitment has ended.