How do I make an art portfolio?

Are there specific schools you're interested in applying to? A lot of the time the requirements for a portfolio can change between schools and sometimes they want it submitted in a specific way or want specific requirements. I'd first start by looking at the websites of the schools you're interested in to see what they are looking for. I'd find it weird if a school wants you to submit a music portfolio but not specifically tell you what they want submitted.

I'd look to upload your music in MP3 format and try to show a range if at all possible. If you've composed your own music then definitely include that in the portfolio. You'll probably need to include some type of resume where you list the music you've written/played, where/why you played it, special music experiences and awards, etc. You might need to submit scores you've written as well but again, I think this varies by school. If you edit the post to include where you're considering I can try to give more specific information but I hope this at least points you in the right direction.

So as someone semi-interested in architecture I believe I can help.

First of all assuming electronic portfolio is preferred Id recommend a google slides/pdf/google sites etc version what ever you prefer.

First upload a picture/digital copy of your art onto your portfolio and then possibly put a small blurb.

Then you repeat unit you have somewhere between 10-20 pieces.

For music either have it in mp3 format or on youtube INCLUDE LINKS and as for what music id recommend in your opinion your best piece(s) and possibly an experimental one.

(Example if you regularly do pop pick something out of your comfortzone like rap or country)

I don't know if you should put a blurb detailing why you made it what it means how you made etc I do not know you should ask a admission rep for your top school.

Some links

https://www.format.com/magazine/resources/art/how-to-make-art-portfolio-college-university

https://www.studentartguide.com/articles/how-to-make-an-art-portfolio-for-college-or-university

Hope this helps!