Pls help me turn off two factor authentication some one accidentally turned it on

Sorry, not possible to reverse the process. See the FAQ in the document linked below:

Two-factor authentication for Apple ID - Apple Support

Might be a separate discussion, but no one else should have been able to turn on 2 Factor unless they had access to your Apple ID and Password.

as is commented near the bottom of the link you came here from in the FAQ section..

Can I turn off two-factor authentication after I’ve turned it on?

If you already use two-factor authentication, you can no longer turn it off. Certain features in the latest versions of iOS and macOS require this extra level of security, which is designed to protect your information. If you recently updated your account, you can unenroll within two weeks of enrollment. Just open your enrollment confirmation email and click the link to return to your previous security settings. Keep in mind, this makes your account less secure and means that you can't use features that require higher security.

They may have turned it on because they enabled an Apple Service that requires it (messages in iCloud, HomeKit, iCloud keychain, Apple Pay, etc).

And when you say "some one", why is anyone enabling settings on your AppleID? Everyone should have their own AppleID. They are personal Apple online service login IDs and are not meant to be shared.