I have an iPhone 5s that I got from a friend & the power button is extremely hard, next to impossible to push is. Is there another way I can take screenshots?
You can use Assistive Touch. Enable it from Settings → General → Accessibility → Assistive Touch, then to take a screenshot you can tap the Assistive Touch button and choose Device → More → Screenshot. The menus can be customised in Settings to provide easier access to the function if you use it often.