What is the best practice of displaying this tooltip: on click or on hover?
I will still need a clicked version for tablet. Should the popup have a close icon in this case, or can I rely on tapping outside?
Hover indicates quick passive intake of information. If they need to do something, such as click on a link then it needs to stay open and it should be on click with a close option. It is too hard for people to take actions in purely hover states.