i've change my apple id on laptop but on my iphone its still old id so i still cant get apps on my phone

To change which Apple ID you want to use with your iPhone for iTunes & the App Store, you would use the Settings app on the iPhone, as follows:

• Select Settings
• iTunes & App Store
• Select the current Apple ID that is showing.
• Select Sign Out.

Then select Apple ID again and enter the one you want to use.

THANK YOU SO MUCH!!!!

How can you sign out if it won't let you sign in. It won't take my password.

If you forgot your Apple ID password, you will need to reset it.

Ref: Apple Support - If you forgot your Apple ID password

• To reset your Apple ID password:
  • You'll need to know the email address for your Apple ID. If you're not sure which email address it is, there are a few methods to find your Apple ID.
  • After you enter your Apple ID, you can change your password.
• Answer your security questions.
• Use email authentication.

It is only showing the new ID. But the OLD ID keeps popping up and asking for password. Old password doesn't work. New password doesn't work.

See my response to gator1943.