can i delete photos from my i pad and access them from i cloud

Apple gives such a tip:

How do I turn off iCloud Photo Library on just one device?

You can turn off iCloud Photo Library on a single device when you follow these steps:

• On your iPhone, iPad, or iPod touch, go to Settings > iCloud > Photos and turn off iCloud Photo Library.
• On your Mac, go to System Preferences > iCloud > Options next to Photos, then deselect iCloud Photo Library.
• On your Apple TV (4th generation), go to Settings > Accounts > iCloud and under Photos press Select to turn off iCloud Photo Library.

If you have Optimize Storage turned on, you might not have all of your original photos and videos on your device. To download the original photos and videos on your iOS device, go to Settings > iCloud > Photos and select Download and Keep Originals. On your Mac, open Photos, choose Photos > Preferences, then select Download Originals to this Mac. Then you can turn iCloud Photo Library off. You can also select the photos and videos that you want to download from iCloud.com.

See more in this article:

Get help with your iCloud Photo Library - Apple Support

iCloud is a syncing system, not an external 'hard drive'. If you delete them on your device, they will delete from iCloud. To increase space available, go Settings/iCloud/Photos and select Optimize iPhone/iPad Storage. That will reduce the space required by about 90% when fully effective.