If location services were on when a photo was taken, there's a good chance the exact latitude and longitude are sitting inside the file itself — readable by anyone who opens its metadata, whether or not the photo shows anything identifiable. Turning off "location for camera" in your settings only stops future photos from being tagged; it does nothing to photos already sitting in your camera roll or already sent somewhere.
Stock iOS doesn't include a metadata editor in the Photos app, so you can't strip GPS from a photo that's already been taken through the built-in interface. Two practical options:
Coverage varies by manufacturer and gallery app, but in the stock Google Photos app: open the photo, tap the "i" info icon, and if a map/location is shown, look for an edit option to remove it. Not every device or gallery app exposes this, and it doesn't touch other metadata fields (camera model, timestamp) even when it does remove location — a dedicated tool covers all of it in one pass.
Right-click the file → Properties → Details tab → "Remove Properties and Personal Information" near the bottom. You can create a copy with everything stripped, or select individual fields (including GPS) to remove. This works well for JPEG and TIFF; support for newer formats is inconsistent across Windows versions.
Preview's Inspector (Tools → Show Inspector → GPS tab) will show you a map of where a photo was taken, but current versions don't include a one-click way to delete that data from the file. The reliable route on Mac is the same as the others: a tool built specifically for reading and stripping metadata.
Because none of the built-in tools above cover every field on every format consistently, the fastest cross-platform approach is a browser-based tool: drop the file into Nullframe's Remove mode, and it strips GPS along with the rest of the EXIF/IPTC/XMP block — for JPEG, PNG, and WebP, entirely on your device, without the file ever being uploaded.
Get in the habit of checking a photo before it leaves your device, not after. Once a file has been sent, emailed, or uploaded somewhere, any copy that already exists elsewhere keeps its original metadata regardless of what you do to the copy on your phone afterward.