The spotlight is a desktop search feature which was initially used in macOS, which is now part of the iOS device. Spotlight in iOS comes with a lot of features which is not known to everyone.
To start Spotlight, touch your finger anywhere on the home screen and drag down to reveal Spotlight search field. In IOS, Spotlight can be used to find almost anything in iPhone and iPad
Some functions that can be done using Spotlight on iOS 10
Search for Apps
Search for a word and if a match for the word appears in another App, Spotlight will show you the 3 best matches followed by a Search in the App. If you select Search in the App, it will be opened without having to open the App separately.
Search for location
Search for a location or place, even street names. The search results will be automatically listed in the list. Clicking on the listed search automatically opens the location in Maps.
Search for contacts
Enter the name of a contact that you would like to contact urgently. The search will pull out all names with the information you entered. The contact card displays the option to make a FaceTime call, send a message or directly call the number.
If you find it difficult to locate a particular App from any of the desktops, simply use a Spotlight search on App name. Type the App name and it will be listed in the results. Click it to open the App.
Simply ask a question to know the answers quickly. For e.g., type kg to pound or dollar to euro or pi to simply get these values.
Do simple Mathematics
Spotlight can be used to make calculations. Simply enter the digits that need to be calculated. This option can only be used for making simple calculations, not the scientific calculations.