The short answer: use the browser, skip the app store
Most guides to blurring photos on a phone are lists of apps to install. You don't need one. Blurify's editor runs in the mobile browser on both iPhone and Android, with touch controls sized for fingers: drag a region's corners to resize it, drag the middle to move it. Faces, license plates and screens are detected automatically the moment the photo loads; anything else, you cover with a drawn rectangle.
Because it's a web page and not an app, there's nothing to update, nothing asking for photo-library permissions beyond the one image you pick, and nothing to delete afterwards. The photo goes to encrypted storage just long enough to process and is deleted within an hour.
On iPhone
Open the editor in Safari and tap the upload area — iOS offers your photo library directly. HEIC, the format your camera actually shoots, works as-is up to 20 MB, so there's no export-to-JPEG dance first. Anything the detector finds is outlined when the image appears; tap a region to change its style, or drag a new rectangle over whatever else needs to go.
The built-in alternative is Markup in the Photos app, and it gives you a pen, not a blur. An opaque scribble works if you're careful to cover everything, but it looks like a scribble. Blur, pixelation or a clean solid block reads as deliberate and doesn't draw the eye the way ink strokes do.
On Android
Same flow in Chrome: open the editor, tap to pick the image, adjust the outlined regions, export. Google Photos on Android has markup pens and background-style effects, but no tool for blurring an arbitrary part of the image — which is exactly the case this covers: a name in a screenshot, a street number, a face in the background.
The export re-encodes to JPEG, WebP or PNG at your choice, so what you post is a normal image file that any app accepts.
Why not just scribble over it?
Two reasons. Cosmetically, ink strokes look like redactions from a crime drama and pull attention to the exact spot you wanted people to ignore. Practically, markup tools tempt you toward semi-transparent strokes — a highlighter swipe over a name — and a semi-transparent cover can sometimes be brought back to readable with a simple brightness and contrast edit.
Blurify's styles are destructive pixel edits: the export replaces the original pixels in the covered region. A pixelated or solid-filled area carries none of the original detail underneath, no matter how the file is edited afterwards.
The metadata your phone wrote into the file
Phone photos carry EXIF metadata, and that usually includes GPS coordinates of where the shot was taken. If you're blurring a photo for privacy, the location baked into the file matters as much as the pixels. Every Blurify export strips EXIF and GPS automatically — nothing to remember, nothing to toggle.
More on EXIF removal