To increase your volume all you need to do is eat more and exercise less- no linux required.

Even though you have provided absolutely no relevant information-
Which linux distro are you using?
which desktop environment is installed?
KDE
gnome
lxde
cinnamon
etc-
I shall attempt to answer your question based on a couple of assumptions:
1) A modern linux distro is installed
2) A desktop environment providing a desktop and taskbar is installed

A)If you don't see a volume icon in systray try right-clicking on taskbar and see if option to add widget or application is available.

B) If no joy with A then look in menus for a mixer application most will put a volume icon in tray when started.

C) If neither A nor B works or if assumption 2 is wrong then open a terminal-
xterm
urxvt
konsole
lxterminal
Whatever terminal emulator you have installed-
and at the prompt type 'alsamixer' sans quotes.
Adjust to your hearts content.

hth