How to gift an iPhone to a friend?

How to gift an iPhone to a friend?

Added (1). So I want to buy an iPhone for my friend for Christmas but I'm wondering how to go on about it. (She doesn't live in the same state as me so I'm planning to ship it to her). I want to buy just the phone for her but I'm wondering if it is possible for her to put it on her family plan/contract. Also do I buy an unlock iPhone for $15/month on the same carrier that she is using so she can just put it in her plan? I'm not sure how to buy just the phone and the rest she can figure out herself

IPhone sending messages to other people?

So for the past few days, whenever I text my parents, like if I text my Mom my dad will get it or if I text my dad my mom will get it. When I try sending a message to either, I'll get the ones my mom and I were on but it'll have a different number on top. I checked iCloud and not any of us are sharing the same address, we just share the same account. I hard restarted my phone thinking it would help but it didn't. My phone made a static noise twice, I'm also being told by my iPhone that the battery has been degraded. I'm not sure /what/ to do. I'm absolutely sure my phone is slowly dying though.