Dear Aspirant

Portfolio is nothing but a good record or a file that consists of all your work. 

Having a good portfolio really helps. They are few colleges who ask for pprtfport after the first phase of the entrance exam. U will need a portfolio to Get into NID. Having a portfolio is always useful, it will fetch u good internships also.

If you are applying for Bachelor of Design at Nift, you don't need a portfolio. Because you don't have a personal interview or any personal interaction rounds. For B.Des, you will have to give CAT, GAT and then the Situation test, all the evaluation is based on your performance in the three tests. However u will need a proper portfolio if you are applying for M.Des, diplomas and PG diplomas in design.

Every college has its own process of admission. As a design aspirant, work on your skills. Concentrate on drawing, shading and perspective drawing. Focus on human illustration and proportions. Have a simple portfolio, keep all your good work in it, which would highlight your skills and keep polishing your skills. They are few private colleges which call for interviews and portfolios. Eg. UID, Ahmedabad, it's is one of the top design colleges in India and they ask for a portfolio to select the deserving students. 

So have a portfolio, keep practicing and improving your skills and update it. Focus on what you want. Being clear about what u want will enable you to bebeffective. Apply for intrested colleges and courses, submit/showcase your portfolio if needed.

You can go through information in Careers360 to find top design colleges. Download the e-book for better knowledge. Here is the link

https://design.careers360.com/download/ebooks/top-design-entrance-exams-in-india?icn=ebook-view&ici=ebook-view_related-ebook

Design is a very competitive field, one has to be ready for it, you portfolio should showcase that you are ready and you have what it takes. 

Feel free to ask the questions further

All the best.