Delete old iCloud address from ipad without using a macbook

You do not provide much background indicating what the real issue is. To remove and ID from a device, usually all you have to do is sign out of it. It is possible you have it set in several locations in which case you then need to sign out in each of those places or erase your device entirely.

Read this document to learn how to sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac --> Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac - Apple Support

For an Apple mobile device:

1. Go to Settings, then tap your name. 

2. Scroll down to the bottom.

3. Tap Sign Out.

4. Enter your Apple ID password and tap Turn Off. (Read this if you If you forgot your Apple ID password - Apple Support ) 

5. Turn on the data that you want to keep a copy of on your device.

6. Tap Sign Out.

7. Tap Sign Out again to confirm that you want to sign out of iCloud.

How to factory reset your iPhone, iPad, or iPod touch - Apple Support - "Learn how to wipe information from your iPhone, iPad, or iPod touch and restore your device to factory settings." Tap Settings > General > Reset (scroll all the way to the bottom)