Can you assist me on how to unlock my iPhone?

How is it locked?

• Screen locked because you forgot the lock code—>If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support
• Phone is Activation Locked—> You need the Apple ID and password used to enable it. There is no way around this.
• SIM PIN locked: Contact your carrier for a PUK code
• Locked to a carrier: Contact the carrier it is locked to and ask about their unlocking policy
• Apple ID locked—>If your Apple ID is locked or disabled - Apple Support

Define "unlock".

If it's carrier locked, you will have to work with the carrier it's locked to. They are the only ones who can unlock it.

If you forgot the passcode, see this document: If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled

If it's activation locked, only the owner of the account used to lock it can remove the lock.