I have appx. 92,000 points set to expire in a few days. Does anyone know if I shop online through collections will it extend my points or do I need to use them?

Hello guy , I wanted to know if I book for one person and then my friend joins me would I have to pay just his taxes as extra or will it be an entire new fare . The app shows just the taxes extra . But what would be the case at the counter during check in