Open the Photos app
Tap the Photos tab
Select a photo
Tap Edit
Use the controls:
Adjust: drag sliders for Light, Color, Black & White, and More
Crop and Straighten: drag corners to crop; use the straighten slider
Filters: select a filter and adjust intensity if available
Retouch: use the tool to remove minor blemishes
Red-eye: tap to fix red-eye if available
Markup: tap the markup icon to draw, add text, and add shapes
Rotate: use the rotate option or rotate controls
Tap Done to save changes
To revert to the original, tap Edit, then tap Revert
To copy edits to other photos, tap Edit, then Copy; select other photos and tap Paste
To undo a specific change, tap Edit, then use Undo (if shown) or adjust sliders back
To save a version instead of overwriting, choose the option to Save as Copy (if shown)