Can I ask a stupid question?

[Mitzy]

If I move from a contract to a sim only deal can I keep my existing mobile number? also if I move to a sim only is it easy to store all my data on the phone rather than the sim so I don't lose all the stuff on my phone when I change the sim over.

Thanks  

[Cleoriff]

Hi @Mitzy It's easy to keep your number when changing from contract to sim only . If the sim fits the phone you are using then leave it in. You wont lose anything on your phone

https://www.o2.co.uk/help/phones-sims-and-devices/how-to-keep-your-mobile-number

Has your current contract ended? If so you can just change to simo by calling CS on 202.

[MI5]

There shouldn’t be anything saved on your sim these days.
Your data should be stored on the phone and backed up to your appropriate cloud server.
What phone are you using now?

[Mitzy]

Thanks for the reply, Iphone 6.

[Mitzy]

Thanks for your reply, I feel I'm almost there....... 

[MI5]

Everything will be saved to your iCloud https://www.apple.com/uk/icloud/
When you login with your Apple ID on a new device, you need to choose the option to restore from backup and all your data will transfer to new device.
If just changing your sim though, it's not necessary as everything will be on the phone already.