Go to "Settings".

Tap "Accessibility".

Swipe up to find and tap "Accessibility Shortcut".

Select the features to add to the Accessibility Shortcut by tapping on the name of the feature.  A checkmark will be shown beside the selected features. 

Once at least one feature is selected and a checkmark is beside it, press the "Home Button" three times (triple-click) to show the Accessibility Shortcut menu.  (If only one feature is selected, the feature will turn on right away when the Home Button is triple -clicked).

Tap the name of the accessibility feature to turn it on. It will now be ready to use.

 In the image above, "Zoom" is the selected feature.  Once it was tapped, the Zoom Lens appeared on the screen). To turn off the accessibility feature, triple-click the "Home Button".

Then tap the name of the feature to turn it off. 

Swipe down from the top-right corner of the screen to open Control Center.

Touch and hold anywhere below the Control Center icons.

Tap "+ Add a Control".

Use the Search bar and Keyboard to type "Accessibility Shortcuts", then tap the "Increase Contrast" icon to add it to the Control Center.

Tap anywhere on the screen to finish editing the Control Center.

Tap the "Accessibility Shortcuts" icon (A list of the accessibility features that were added to the Accessibility Shortcut will be shown on the screen).  Then select an accessibility feature.

To turn off the accessibility feature, swipe down from the top-right corner of the screen to open Control Center, then tap the "Accessibility Shortcuts" icon.

Tap the name of the feature to turn it off, then swipe up from the bottom of the screen to exit the Control Center.