When you are making Instagram photos of your friends, you can also tag them in the photo. Here is how to do that.
- Access your Instagram and tap the shutter button in the middle to take a photo.
- Edit your photo with various filter and Instagram photo editing tools. 
- Tap the forward arrow button in the top-right corner.
Tap “Tag People”
- On the “Share to” page find the “Tag People” button and tap it.
- Tap anywhere on the photo to tag people you want to appear on the photo.
- Type in the name of your friend in the searching field. It will suggest someone from your followers according to the name you have typed in . Select the one you want to tag.
- Drag the tag to move it or tap the photo again to delete the tag.
- Tap when you are done. 
- You can choose to add a description to the photo.
- Tap in the top right corner to share your photo.