How to unlock your phone?
Check if your phone is unlocked. Many phones, such as Verizon phones that support 4G LTE or most Android smartphones, unlock as soon as you buy them. Also, many carriers unlock your phone once you meet the unlock conditions.
Make sure you meet your carrier’s unlock criteria
Sprint – Your phone must be at least 50 days old, and you must own the phone (for example, you must pay in full). Additionally, the phone should not be reported as lost, stolen, blocked, or involved in illegal activity.
American Telephone and Telegraph Company. AT&T cannot report your phone as lost, stolen, blocked, or engaged in illegal activity. Your phone must also be fully paid and be on the AT&T network for at least 60 days (prepaid phones must be at least 6 months old). 
T moves. T-Mobile must not report your phone as lost, stolen or locked, your account must be current for payment, and you must have received more than two unlock codes from T-Mobile. past 12 months Check your phone’s IMEI number.
You must provide your carrier with your phone’s IMEI number (or, for some CDMA phones, MEID) to unlock your phone. To find the IMEI number:
iPhone: Open Settings, scroll down and tap General, tap About, and look for IMEI, MEID, or ESN number.
Android: Open Settings, scroll down and tap About Phone, tap Status, and find your phone’s IMEI, MEID, or ESN.
Make sure you have your account information. You’ll need to provide your carrier with your account information, so get everything you need before contacting your carrier.
Get the unlock code.
Call your carrier and ask to unlock your phone and give them the required information. If you’re eligible to unlock your phone, your carrier will give you a multi-digit code that you can use to unlock your phone.
For some carriers, you can visit the carrier’s website, log in and enter your phone’s details to receive an unlock code.
You may have to pay to unlock your phone.
Determine the mobile type of the phone.
There are two main cellular standards – CDMA and GSM – that determine which carriers your phone can use. Your current carrier’s hardware may not work with other carriers, so it’s important to understand who made your phone and who might be using it before continuing.
If the phone is built to be unlocked, you need to know what type of phone it is before proceeding.
Buy a SIM card from your favorite provider.
You need a SIM card to use this provider’s network.
It’s best to buy SIM cards from your carrier’s store, as they will help you set up the correct SIM card for your phone.
Insert the new SIM card into the phone.
This process includes turning off the phone, removing the current SIM card, installing a new SIM card, and turning the phone back on.
Enter the unlock code.
Some phones require you to enter a passcode to unlock the screen before you can unlock the phone yourself.
If your unlock code doesn’t work, please contact your carrier.