Why choose PNG instead of JPG
Most people convert HEIC to JPG, and for sharing photos that's usually the right move. PNG makes sense when you plan to keep working on the image. Because PNG is lossless, you can crop it, add text, retouch it and save it again as many times as you like without the gradual blur that comes from re-saving a JPG.
That's why designers, people preparing images for print, and anyone pasting iPhone pictures into graphic projects often prefer PNG. It's also the format many editing apps, slide tools and sign-making programs handle most predictably.
Real reasons people need it
You photographed a hand-drawn sketch, a signature or a product on a plain table with your iPhone and want to remove the background later; a PNG is the right starting point for that. You need to drop screenshots or photos into a document on a Windows PC that doesn't open HEIC. A teacher or a client asked for PNG files specifically. Or you simply want a version of your photos that opens on any computer without extra codecs.
Once you have the PNG, the other ConvertirDocs tools can take it from there: “Remove white background” makes a plain background transparent, and “Resize image” sets exact dimensions.
Which browsers can open HEIC
ConvertirDocs reads HEIC with your browser's own decoder, so it depends on the browser and the device. Safari on iPhone, iPad and Mac opens HEIC. Chrome can too when the device has an HEVC decoder, which is common on Macs, Android phones and many Windows computers with compatible hardware. If your browser can't open the photo, the site tells you clearly instead of producing an empty file.
If that happens on a computer, the simplest fix is to open ConvertirDocs in Safari on the iPhone where the photos are and convert them there.
File size and privacy
HEIC is very compact and PNG is not. A photo converted to PNG can be several times larger than the original, which is the price of keeping every pixel exactly. If you only need to send pictures, HEIC to JPG produces much lighter files.
The photos are converted on your device and never uploaded. EXIF data, including the GPS location iPhones record, isn't copied into the PNG, and the camera orientation is applied so portrait photos stay upright. There's no account and no limit, and ConvertirDocs is 100% free.