Can spyware be put on my phone without having possession of it?

Hi!

Yes, this is possible, since nothing is perfect.

BUT I have some good news for you buddy! Since you're rocking an iPhone and iPhones are really restricted it a lot of ways unlike Android, but some of these restrictions are meant to make a device as secure as possible.

My favorite example is an impossibility for an app to access your SMS on iPhonea, meanwhile it's possible for a app to read and do whatever it wants with your messages on Android and only recently Google added a quote asking "do you want to provide an access to your messages for that app?". From my perspective, there are no app I'd ever want to access my messages, since nobody can guarantee that it's not sending it somewhere and there is a critical information in my messages.

So now we know that the device choice is good. But there are still some recommendations to keep your phone clean:

• Never do any kind of hacking/Jailbreaking/Installing certificates or anything like that to your phone. If you want crap, that you can get after Jailbreaking - get an Android and you'd get it out of the box without using hacking tools from unknown developers who can do anything they want with your device.
• Install apps only from the App Store. And while doing so, use common sense while deciding if you need an app or not. App Store is the safest place you can find, but again, nothing is perfect.
• Make sure you're firmware is always up to date. You can turn on an auto update for your iPhone, to make sure you're always rocking the latest and greatest. Apple is really careful with the security and there was cases, when they've released an update in 1-2 days after some critical vulnerability has been discovered, so you can feel safe.
• And some don'ts - don't open unknown links you don't really need or it looks fishy. Don't do some weird things people may tell you to do for no reason. Don't let other people have physical access to your phone even if it is locked. Don't use not original cables and chargers (yes, they may contain spyware). Don't use any public USB wall outlets - they may ruin your battery or/and steal your data.

spyware, malware, addware, virus.... are all software

on an ios device the only place one can get new software on a device is apples app store

you can't get software from websites, mails, sms's from your computer ,.....

so only if spyware trick apple and get into your device along with an app you install can it reach your phone

though many people often think software bugs or other device behavior they don't expect or understand as virus or hacking or the likes