How do I unlock my iPhone X?

Do you mean Activation Lock, where the screen says Locked to Owner? That would require the Password or original purchase receipt from Apple or Authorized Apple Seller. Those that purchase used phones where they were not properly erased, or even stolen, and unable to contact the seller for removal of their account will find they purchased a brick and will not be usable. If it is the Activation Lock and you have the original purchase receipt from Apple or Authorized Apple Seller, the website for removal after submitting that documentation is here:

https://al-support.apple.com/#/al/agreement

If this is your Apple Account that is Locked, then review this Support Article for steps to take where you may be able to regain access to your account.

If your Apple Account is locked, not active, or disabled - Apple Support

If the phone is Carrier Locked, then you will need to contact the cell provider that has locked the phone.

Please update with what kind of lock you are experiencing and we may be able to provide a more detailed explanation.

Unlock what? Carrier lock or Activation lock or Passcode Lock or Security Lock?

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

To be able to use any SIM across the globe you must have "No SIM Restriction" against Network Provider Lock. Please refer to the pic below.

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

Device Unlocking Policies | Verizon Privacy Policy

Unlock a Phone or Device - AT&T Device Unlock Portal

Unlocking your Sprint device - T-Mobile

FAQs about unlocking your Sprint device

Unlock Your Phone for Spectrum Mobile

If you are the owner or the owner has shared all information with you then open Activation Lock:- If it is Activation locked, read here --> Turn off Activation Lock - Apple Support Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Learn how to remove a device from a previous owner's account.

If you are not the owner and do not have the Apple ID and Password then there is no way that you can get into this iPhone unless the original owner shares the Apple ID and password with you. If you are lucky you can get into this iPhone if they (the owner) accidentally remove the device from their Apple ID.

Lock Screen Passcode

Following this process is the only way out if your iPhone is disabled. The steps given in this link will help you reset the passcode -> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...

If you see an iPhone or iPad unavailable message or a "Security Lockout" screen

If you forgot your passcode, you can use your Apple ID and password to erase and reset your device without a computer.

Learn what to do if you see "[Device] unavailable" or "Security Lockout" on your iPhone or iPad.)

sirajul34 wrote:

Apple

​"Which ID is my Apple ID connected to? Is it connected to this ID or another one? If you check, you will find out. Please check it once."

You are not talking to Apple. This is a user forum. We can't tell you what account it's locked to. Neither can Apple. If you don't remember and can't figure it out, there is no way to remove the activation lock unless you can provide Apple with the original proof of purchase AND the device is not in lost mode.

sirajul34 wrote:

Apple

​"Which ID is my Apple ID connected to? Is it connected to this ID or another one? If you check, you will find out. Please check it once."

Your Apple ID is not connected to another Apple ID. Your device is locked to a single Apple ID, that is only known by the person that set it up and you should see a partial email address to give you a clue. If that partial email address means nothing to you, then your only other option is to provide the original purchase receipt from Apple or Authorized Apple Seller to remove the Activation Lock with the link that has already been provided.

Thank you for reaching out. 😉

If you are not the original owner, then Activation Lock is a security feature to protect the owner from theft. In that case, only the original owner can unlock it. 🔓

↓ If you are the original owner: ↓

According to Apple:

Remove Activation Lock on the device

Follow the onscreen steps to enter the Apple Account and password you used to set up your device or your device passcode. If you don't remember your Apple Account, try to sign in with an email address or phone number that you regularly use for Apple services.

Learn how to find your Apple Account or reset your Apple Account password.

If your device is owned by a business or educational institution, please contact your IT department or manager. 

Remove Activation Lock on the web if a device is offline

For iPhone, you might be able to remove Activation Lock on the web even if your device isn't offline.

1. Go to www.iCloud.com/find.
2. Sign in to your Apple Account.
3. Select the device that you want to remove from iCloud.
4. Click Remove This Device.

Start a support request

If you need help removing Activation Lock and have proof of purchase documentation, you can start an Activation Lock support request.

Thanks again for reaching out. 👍🏼

Smiliñ 😎 Brian

Since you do not have the original sales receipt for the phone, Apple will not unlock it. (If it is in Lost Mode, say because the original owner marked it as Lost, or because you logged into a scammer's account, Apple wouldn't unlock the phone even with that receipt.)

It also sounds like you do not know the Apple Account credentials needed to unlock the phone yourself.

If this is a second-hand phone, and you discovered, after buying it, that it was Activation Locked, see

The All Too Common SAD Reality of Buying a Used iPad/iPhone – Apple Community

What is the actual message that you see on your iPhone screen?

Activation Lock?

Unavailable?

Something else?

I'm sorry, but there is nothing anyone here can do about it.

This is not the original sales receipt that displays the date of sale from an authorized dealer, serial number and name of the person that purchased the phone.

I'm sorry, but you will not be able to unlock the phone without the original sales receipt that displays this information.

There are no other options.

Did you even bother reading anything in this thread before posting?