I am quite new in LaTeX and I am using TexMaker. How can I remove some of its output (such as .aux, .out, .synctex) and just see the .tex and .pdf files?
As stated in the comment, use the clean tool or set to use clean tool on exit in the preferences. But be sure to quit and not just close the file.
Especially when having many files open this isn't always possible, so I made a small bat script that deletes nearly all types of output files in the folder it sits in and its sub folders:
del /S *.log del /S *.lof del /S *.out del /S *.synctex.gz del /S *.aux del /S *.bbl del /S *.lot del /S *.blg del /S *.tdo del /S *.toc
just add any extensions you might encounter and save the file as a .bat using your favorite text editor and place it in the root folder of your latex project(s). Obviously use different commands and options for linux...
Trying to prevent the creation of auxiliary files is a very bad idea - as well as deleting them after every run. Latex needs them in many instances to produce correct output. But if you don't want them in your directory, a possible solution would be the LaTeX build wrapper ltx2any. This does not prevent the creation of all the auxiliary files, but places them in another directory, which you can specify
ltx2any -t path_where_you_want_the_auxiliary_files_to_go filename.tex
This path can very well be a
tmp folder, so you will not see these files again, but latex can access them.
For more options, see