How can I remove all photos from my iphone?

Hi pjdemeo,

I understand you want to delete all of the photos from your iPhone. As a precaution, I would suggest importing the photos and videos from your iPhone into your computer. This will give you a backup for the images, and after import you will be asked if you want to delete the photos.

Import photos and videos from your iPhone, iPad, or iPod touch to your Mac or Windows PC - Apple Support
https://support.apple.com/en-us/HT201302

The iPhone User Guide has instructions for deleting photos directly from the device:

Organize photos and videos - iPhone
http://help.apple.com/iphone/8/#/iphf14943e

Delete a photo or video from Photos. Tap the Photos tab, tap the photo or video, tap , then tap Delete Photo or Delete Video. Deleted photos and videos are kept in the Recently Deleted album on iPhone, with a badge showing the remaining days until the item is permanently removed from iPhone. To delete the photo or video permanently before the days expire, tap the item, tap Delete, then tap Delete Photo or Delete Video. If you use iCloud Photo Library beta, deleted photos and videos are permanently removed from all iOS 8.1 devices that use iCloud Photo Library beta with the same Apple ID.

Cheers,

- Judy