I expected latex to automatically display the first letter after a period in uppercase, as I'm used to in MS Word, but turns out it doesn't, and I can't find anyone mentioning this on the internet nor all the latex documentations I checked. I'd really appreciate the help.
In opposite to Word, LibreOffice and the like, you have to distinguish cleary the editor from the »LaTeX« machinery. The editor is used to type the text. So if you'd like to have a kind of autocorrection, find an editor who does this job for you. There is a real long list here: LaTeX Editors/IDEs
After saving the file your texlive / miktex / whatever installation produces a PDF from your file, but it does not change the *.tex file. You just get a PDF and some auxiliary files.
By the way, you could even use the word window as editor. If I'm to lazy for proof reading, I sometimes copy my text into a word window and wait, what Word marks up as error.