if I want to do my preparation of Bdes entrance NIFT exam with any learning app.. so name of the most important app for for this exam?

To prepare for BDes Entrance exam for NIFT, you need to focus on three sections and those are Creative Ability test, General Ability Test and Situation Test. NIFT Entrance examination is all about how much creative you are. These tests will determine your ability to think and create, how much genuine your thinking is. You can surely take help from various websites and applications but you're instructed not to copy them. General ability test will check your Quantitative ability, analytical ability, communication skills, general knowledge and current affairs. Practice with various materials like cardboards, Foam sheets, velvet papers, Glues, pins, Clays, Rubber Bands, Thread, Fabric, plastic sheets, marble papers and other type of crafting materials. Practicing with these enhance your thinking ability, makes you more creative.
There are various way one can learn from the internet. YouTube channels like Ignite India Education, Silica Institute, Addylabs etc you can follow for BDes preparation. Careers360 help design aspirants in their preparation. You can check last few years' situation test questions which can help you in your preparation http://design.careers360.com/articles/nift-situation-test
http://design.careers360.com/articles/nift