LaTeX problem with the fancyheader package

Relatively new LaTeX-user here. I have been running into a lot of problems with the fancyhdr package. The fancyhdr commands do not seem as if they are registering at all but the code runs into no errors. In addition to this, changes I make to text like my title or anywhere else in my document do not appear. Yet when I omit the line that imports fancyhdr, the change I made to the title of the page (sample title to Yolo) suddenly appears and everything works again (except I still have no header D’:
).

I attached the exact code I have below in which nothing is changing (the title does not change to "Yolo" and the header does not appear with the fancyhdr package). I am looking for some way to get fancyhdr to work but I have been unable to resolve it. Searching online, I feel like this could be a pagestyle problem but I am unsure how to rearrange my code in order to completely fix this.

I am currently using Texmaker to edit and code in LaTeX.

    documentclass[11pt]{article}
    usepackage[margin=1in]{geometry}
    usepackage{amsfonts,amsmath,amssymb}
    usepackage{graphicx}
    usepackage{float}
    righthyphenmin12
    lefthyphenmin12
    usepackage{fancyhdr}
    pagestyle{fancy}
    fancyhead{}
    fancyfoot{}
    fancyhead[L]{MakeUppercase{title should go here}}

    begin{document}
    begin{titlepage}
    begin{center}
    Hugetextbf{Yolo}
    Largetextbf{sample subtitle}[4mm]
    vfill

    line(1,0){400}
    Hugetextbf{sample title}[3mm]
    Largetextbf{- sample subtitle -}[4mm]
    line(1,0){400}
    vfill
    Professor: Chuck E Cheese
    University of Potatoes
    September 12, Fall 2020
    end{center}
    end{titlepage}

  [1]: https://i.stack.imgur.com/p3tEW.png