Uploading to the App Store is actually quite a process. Usually, you’ll need a paid (99$/year) Apple Developer account – and with this account you can upload your app in iTunes Connect.
There are tons of articles available on what all the steps are, like this one:
But, since your app is for personal use only, then you can also install your app on your phone using Xcode. You don’t need a paid developer account for this – but you’ll still need to ‘wrap’ your app in a WebView and build your app. Some technical knowledge is recommended for this. After you did this, you just connect your phone to your Mac and install your app on your iPhone.
Buuuutttt… I’m assuming your app was made with Bubble, right? So it’s a web app anyway. In that case, just use the ‘Add to Homescreen’ button in Safari. This is by far the easiest solution. Just follow the steps in this forum post: Hide the address bar in the browser when on mobile or specific pages on desktop (FullScreen Experience)