For Unlock iPhone you have to know below 3 steps.

1) Your official Carrier.

2) Your imei Number.

3) Your device is Clean or Block.

a) If you don't know your official Carrier you can use iPhone imei Check .

It's look like this page .

 iPhone imei check for unlock iphone 

For unlock iPhone you have to check Next Tether Policy ID: this will show you your device locked carriers.

Second thing you have to check Next Tether Activation Policy Description: if this show unlock . then device is already unlocked.

b) You have to check your imei number from your device . Go to dial pad and type *#06# it's look like below image.

 how to unlock iPhone for use different carriers sim 

You can also find imei from your device setting . Go to setting > General > About. it's look like below image.

 how to unlock iPhone for use different carriers sim 

Above 2 option is authentic way to find your device original imei .

Now you have your device Carrier and imei in your hand .

Last one you have to check your device is blacklist or Clean.

For this purpose you have to imei Blasklist Check .

Page will be look like as below image.

 imei blacklist check 

If your device show Clean you have to place order as clean . if block then you have to place order as Premium service.

Now you have all information to apply your imei for unlock.

How to Unlock iPhone ? .

Go to Unlock By Brands

 how to unlock iPhone for use different carriers sim 

Select your Official Carriers.

Enter your imei and detail .

Select payment method .

Press Unlock Now.

Page will be redirect to payment page .

Enter your credit/debit card detail .

Press secure pay.

Your order successfully place .

Now you can check your order status by pressing Track Order .

 how to unlock iPhone for use different carriers sim 

DONE.