Hi sorina130,
Welcome to the Apple Community.
Your Apple ID is the account you use to access Apple services,
such as the App Store, Apple Music, iCloud, iMessage, FaceTime and more.
Your Apple ID is usually an e-mail address.
You can enter information to find your Apple ID, if you have forgotten it:
https://iforgot.apple.com/appleid
Your Apple ID and Apple ID password is used to log-in to almost everything Apple.
If you have forgotten the appleID password:
https://support.apple.com/en-au/HT204316
If you forgot the passcode on your iPhone,
(or if a message says that your iPhone is disabled)
learn what to do:
https://support.apple.com/en-us/HT204306
When you have access to your Apple ID account again, you might want to:
Check your Apple ID device list to see where you're signed in.
(You may need to remove some devices, if there are more than you use.)
https://support.apple.com/en-us/HT205064
Hope this helps you :-)