STEPS
TOOLS
First, open Settings
Scroll and open General
Open up "Spotlight Search) Notice how everything is check marked meaning it will appear when doing spotlight search
Un-check them all
Now go to spotlight search and type your web search
And the only options that show up are "Search Web" and "Search Wikipedia"
So now every time you make a spotlight search, you will be able to search the web/Wikipedia instantly
 iOS Device (Including)
 iPhone
 iPad
 iPod Touch

How to use spotlight search for web searches only (ios)

Use SpotLight Search for Web Searches Only (iOS)