Yeah, I've been looking for a portfolio app on my iPad Pro, and puzzled that there's not one out there that I've found! They all seem to be about making websites that you can then have on your iPad ... rather than a replacement for a paper portfolio.
It does depend on each person’s definition of “portfolio,” and a digital portfolio is not always defined as a website. Because the answers so far aren’t working for you, it sounds like you might define “portfolio” in a particular way that we need to know about.
For a lot of people, a portfolio is just being able to display their best photos on their iPad. If the requirement is that simple, you can get there just by throwing a bunch of images into a folder in the iOS Files app, using QuickLook (tap a file) to show the images in that folder full screen on the iPad, and presenting each image in that folder by swiping left to right in full screen mode. If that meets your requirements for a portfolio, no other app is needed because Apple already provides that built-in full-screen image viewer in the Files app as part of iPad OS.
Many other people define “portfolio” as a place online, so that they can always show their best work from any device (tablet, phone, computer…). For this type of portfolio, many photo services provide their own iPad app so that you don’t have to do anything special: As long as you already created an album on their service, you just open their iPad app. People who put their photos into Apple Photos use the Photos app on the iPad. People who keep photos on Flickr, Smugmug, etc. open the iPad app their particular service provides and present from there. Adobe lets you do it through the Lightroom app, Lightroom on the web, or the Adobe Portfolio site.
Other people keep their photos in a cloud folder on Dropbox, GoogleDrive, OneDrive, or iCloud Drive, and they present them from there using the built-in document viewing features in the iPad apps offered by those services. (The app for iCloud Drive is the Files app.) This is not a website, but a cloud synced folder.
So one thing that would help a lot is:
What do you think is missing from the existing solutions, compared to what you want a portfolio to be?
You talked about the suggestions so far not being “a replacement for a paper portfolio.” Does that mean you are not satisfied with showing photos full screen on the iPad (which is possible through many methods as shown above), but you are actually interested in showing your photos composed on some kind of page layout with white space around the photo, and maybe text on the page? If so, then you could use any of the many iPad and desktop applications (including Lightroom Classic) that can both lay out your photos on pages and export that as a multi-page PDF. What’s great is that iOS Files app also has native PDF display, so again you do not need a special app to display it: As soon as you copy that PDF to the Files app on the iPad, all you have to do is tap your digital portfolio PDF document in the Files app to open it full screen, then use the built-in page navigation to show each of the pages in your digital portfolio.
Are there dedicated iPad apps that create portfolios specifically? Probably. But if they create portfolios in their own proprietary file format, then they would be limited to that app, on the platforms it supports, and if the app ever goes away (many older apps are no longer on the App Store or no longer updated), the portfolio can no longer be opened.
That’s why it’s preferable to create a portfolio in a widely compatible format that can survive changes in apps and systems, such as a simple folder of images, a simple HTML website, or a multi-page layout saved in PDF.
