Upload your app version is a really simple process.
Go to https://appstoreconnect.apple.com/login and login with your credentials.
Select My Apps.
Select the app you want to update.
Click in + Version or Platform and select iOS
Write the new version, which should increment the last number. Then click in create.
In the first screen you are going to write what is new with your app (if fixed an issue, improve speed, add a feature, etc.)
Uploading the.IPA file with the latest changes.
Get in your Ordering Builder, Upgrade the version of your Apps with the new changes that you want to show in the Stores after you've done all those changes you have to click the "Store" button in your Builder.
Upgrade the version of your App
Click Store Button
Send for review
Come back to the Appstore connect site, you can check the status of the app in the (1) Activity section. If the app appears as (2)Processing you have to wait a little more time.
Once your upload is processed, this message will be available. Click on it
Select your build version and click in Done.
Normally that is enough, click in save and submit for review.
Select No in all the options and click in submit.
That's it, in your new version should appear the message "Waiting for review"
You can select when to release your app once is approved.
1.- You release manually the application after Apple approve the new version.
2.- Automatically release the application when Apple approve the new version.
Have a Happy Ordering