Not able to transfer photo from iPhone to PC computers

You may want to have a look at this document how to change the settings on the iPhone, so the photos will be transferred as JPEGs instead of HEIC, when you connect it to a computer by USB:

Using HEIF or HEVC media on Apple devices - Apple Support

You have two options - change the setting on the iPhone, so new photos and videos will not use the space saving HEIF format, or to change the settings, so the HEIF files will be transferred in a more compatible format:

• Go to Settings > Photos. In the TRANSFER TO MAC OR PC section, tap "Automatic". This will convert the HEIF files, when importing to a computer that cannot handle HEIF.

1. To disable HEIF completely,  go to Settings > Camera.
2. Tap Formats.
3. Tap Most Compatible. This setting is available only on devices that can capture media in HEIF or HEVC format.
4. All new photos and videos will now use JPEG or H.264 format. To return to using the space-saving HEIF and HEVC formats, choose High Efficiency.

There are other ways you can have a try.

Method 1: Using AutoPlay on Windows 7 (only Camera Roll photos can be transferred)

1. Connect your iPhone to the PC. If the AutoPlay window appears, click "Import Pictures and Videos using Windows".

2. Click the Import Settings link > In the resulting window, you can change the folder to which your Camera Roll's photos will be imported by clicking the Browse button next to the "Import to" field.

3. After setting up your import options, click OK > Choose a tag if desired and click Import button.

Method 2: Photos App for Windows 10 (only Camera Roll photos can be transferred)

Step 1: Download the latest version of iTunes on your computer, and then connect your iPhone to computer with its USB cable.

Step 2: Run Photos App on your PC, and then click Import button at top right corner.

Step 3: Select the photos you want to import to PC, and then click Continue button. And then all the selected photos will be transferred your Windows 10 computer.

There two methods can help you solve your problem with ease. And if you want to transfer all photos including photos in Photo Stream, Photo Library, photos synced from iTunes or computer, iCloud sharing photos, photo albums, etc. Just refer to this article to know more ways to transfer photos from iPhone to PC.