i know this is lazy, but i wrote that answer less then 12 hours ago, so here it is:
that are a lot of questions, with a lot of possible answer. The first question is confusing, i recommend you find a server (here is a list), and use a ftp client (filezilla client) to upload your html files to the server you picked (the server you picked most likely contains instructions on how to do this), if you can't figure out you can search on youtube for this, videos are so much better at explaining, it is really hard to explain it with words only.
What languages should you know? Well, there is tricky one. you could learn mysql (database), there are 3 options which programming language you could pick to build your webapp:
python (scripting language) -> django (web framework)
ruby (scripting language) -> ruby on rails (web framework)
php (scripting language) -> no framework needed, there are frameworks available though
you can access the values in your database with django, RoR or php. How to store the data encrypted? depends on the language you choice, so i leave it open for now.
You have to research which language you want to learn. What the pros and cons they all have etcetera.
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