I am learning User Experience. They says Information Architecture is much important to UX. I am studying about IA in online But I wonder how can I practise it? Please Help. Thanks.
I'm an IA.
Information Architecture is a discipline that can be considered part of the "User Experience" domain. For a good look at this, view "Elements of User Experience" (pdf) by Jesse James Garrett to see where it fits.
Suggested starting point on Information Architecture: read the 'Polar Bear Book': "Information Architecture for the Web and Beyond, 4th ed", Rosenfeld, Morville and Arango. This is the classic text on the field. Its definition of what IAs do: Connect Users with Content through Context is an old one, but the simplest explanation. (f.e., today I've been working on a site section which changes in response to how far down a timeline a user is - it's using the timeline context to get the user the right content).
Boxes and Arrows is a site that has focused a lot on the IA discipline, though it's changed a bit in recent years (as has the IA landscape). It's worth your time to take a look.
The Information Architecture Summit (in Lyons, France for 2018, in the US, most likely, in 2019) is a great place to meet information architects, understand the community, get some starting points. The people who defined the domain are often there, and easy to talk to.
One way to think about what an IA does for a page/site/app/etc. is that the IA designs the information hierarchy so the user can find the important things, so that all things are as findable as they can be, and so the user understands where she is and what she can do at all times in a site.
An Interaction Designer designs user flow through a series of interactions (not necessarily pages)
A UX Designer manages the overall experience of the site, designs it to be coherent and satisfying, while hitting business goals
A Visual designer adds visual flair, while serving the usability, coherence, brand and overall experience of the site.
Information Design is a completely different discipline from Information architecture.
A couple of well-known Information Design leaders are Edward Tufte and Stephen Few. They are concerned with users' ability to understand your presented dataset.
They do this with good design heuristics ("maximize the data/ink ratio") and critique ("don't use chartjunk"), as well as great basic advice ("if you don't have a story to tell, you don't have anything to present". "Steal with abandon. There's no reason to re-solve a problem that has been solved for 100 years").
They also appear on Jesse James Garrett's chart on the Elements of UX.
Hope this gives you some useful tips for where to begin.