how can i change my apple id profile icon/photo?

You can easily change/add a profile picture from iPad settings:

Settings > [Your Name / AppleID]

At the top of the settings window you either see your initials (e.g. “AB”) with an Edit label - or your current profile picture…

Simply tap your initials/existing-picture to expose a menu. From menu, you can select from:

• Take Photo (using the iPad camera)
• Choose Photo (from your Photo Library)
• Browse (select a picture from elsewhere)
• Cancel (aborts the change)

Yes... please see this: Change your Apple ID photo on iCloud.com - Apple Support

If you are referring to the profile pic displayed here in the forums, you can choose any stock pic. To upload a photo or pic of your choice, you need to attacin level 2 (150 points) here.