I want to free space my iPhone internal storage with storing on iCloud

The closest thing you can do, nizanthan, is to turn on iCloud Photo, and Optimize device storage.

Over time, photos that you haven’t used in a while will be replaced by versions that take up less space, while the full resolution versions will remain on iCloud.

Additionally, you should follow the instructions in Clear Other storage on your iPhone or iPad - Apple Support.

(The other suggestions you have received here are also good.)

Looks like you could offload your images to iCloud to save yourself 3.15GB. Other than that, I'd clear out a bunch of those apps... WhatsApp really isn't doing you any favours taking up 6+ GB of space!

To delete some of the data in WhatsApp... go to the app, select Settings > Data and Storage Usage > Storage Used > select a contact to delete images/videos/gifs and clear space > Manage... > select items you want to delete (checkmark) > clear. This will delete conversations also if you've selected wrong, so be careful!

You can't do that.

iCloud storage is for backup and syncing only.

Best you delete stuff you don't need or save stuff onto computer before you delete.

iCloud is not your storage space for photos, it's backup and syncing only.

You cannot off load photos to iCloud.