I want to make an iPhone app? Where to start?

I'm somewhat familiar with HTML, CSS, and JavaScript and want to make an app. I'm thinking of my app looking like a typical app with a tab bar on the bottom that can take you to certain parts of the app. Is there an easy way to create the tab bar interface? I figured using Xcode will make it easier but I'm not sure at all. So I have a few questions and they will seem dumb… 1. My app asks for users to create an account. I know how to make a form for people to sign up and click submit using HTML, however I have no clue what happens after they click submit. How and where is there information saved and what would I need to code this? 2. Is using Xcode smart or should I just use sublime instead and how do I apply my tab bar? Thank you for your help I know this is really newbie stuff but I really want to learn!

My iPhone 6 camera snap sound won't turn off. I have tried everything and it doesn't turn off when I take a picture?

I've turned off the ringer and tried everything. Do you know what would fix it?

Upgrading to a newer iPhone? Is it worth it?

I'm currently using my iPhone 6 that I've had for about close to maybe 3 years now and have been thinking of upgrading to the 8. But, I want to know. Is it really worth it to upgrade to the 8 or stay with what I have. I currently have no issues with my iPhone other than it sometimes dies fairly quickly. But what should I do?

Ihave a new iPhone 7 but I won't let me sign i'm my apple id?

Ihave a new iPhone 7 but I won't let me sign i'm my apple id?

Do I wait for the Note 9 or get S9+?

No, I will not get a mediocre low specced IPhone

How come my camera won't work on my iPhone 7 Plus?

I can take selfies with my front camera but when I switch to my other camera it takes a long time to load. If I use Snapchat it works fine but not when I use the Camera App.

What should I do?

When was the last time you used a GPS before using the iPhone default map or a third party app?

When was the last time you used a GPS before using the iPhone default map or a third party app?

What purpose does iMessages serve on iPhone when you have to be connected to Wi-Fi for it to work?

What purpose does iMessages serve on iPhone when you have to be connected to Wi-Fi for it to work?

What's wrong with my iPhone? - 3

Ok so yesterday my iPhone has been acting really really weird. I'm not getting any notifications and I see that I do when I go on my apps, and YouTube keeps logging me out when I already log in, and I've tried to restart my iPhone multiple times but nothing is working. Why is my iPhone doing this?

Traveling to the Dominican Republic. International SIM card

I will be traveling to the DR in March. I currently have an unlocked iPhone 7 that was purchased from the Apple store. I use a Straight Talk SIM card for service. I would like to used my phone while traveling but don't know how to use a international SIM card or which one will work best. Any suggestions?