How do I transfer videos from my iPhone or iPad to my computer?

Original documentation can be found here - https://support.apple.com/en-us/HT201302

Import to your PC:

You can import photos to your PC by connecting your device to your computer and using Windows Photos app:

1. Make sure that you have the latest version of iTunes on your PC. Importing photos to your PC requires iTunes 12.5.1 or later.
2. Connect your iPhone, iPad, or iPod touch to your PC with a USB cable.
3. You might need to unlock your iOS device using your passcode.
4. You might also see a prompt on the iOS device asking you to Trust This Computer. Tap Trust or Allow to continue.

Then, follow the steps in these Microsoft knowledge base articles to learn how to import photos to Windows Photos app:

• Windows 10
• Windows 8
• Windows 7

When you import videos from your iOS device to your PC, some might be rotated incorrectly in Windows Photos app. You can add these videos to iTunes to play them in the correct orientation.

If you have iCloud Photos turned on, you need to download the original, full resolution versions of your photos to your iPhone before you import to your PC. Find out how.

Photos and videos that you sync from your computer to your iOS device using iTunes can't be imported back to your computer. 

Import to your Mac:

You can use the Photos app to import photos from your iPhone, iPad, or iPod touch to your Mac without using iCloud Photos. These steps also work for importing images from digital cameras and SD cards. 

1. Make sure that you have the latest version of iTunes on your Mac. Importing photos to your Mac requires iTunes 12.5.1 or later.
2. Connect your iPhone, iPad, iPod touch, or digital camera to your Mac with a USB cable. If you're using an SD card, insert it into the SD slot on your Mac, or connect it using a card reader.
3. You might need to unlock your iOS device using your passcode. You might also see a prompt on the iOS device asking you to Trust This Computer. Tap Trust to continue.
4. On your Mac, the Photos app automatically opens. If it doesn't, open the Photos app.
5. The Photos app shows an Import screen with all the photos and videos that are on your connected device. If the Import screen doesn't automatically appear, click the Import tab at the top of the Photos app, or click the device's name in the Photos sidebar.
6. To import a selection of photos, click the ones you want, then click Import Selected. To import all new photos, click Import All New Photos.