How to change the font in the terminal of server?

Try the following command:

sudo dpkg-reconfigure console-setup

The Ubuntu font has no monospaced version, so it's not suited for use in a terminal or console that has fixed width character cells.

In addition, console fonts are special bitmap fonts, not TrueType/OpenType fonts (but OTOH it shouldn't be too difficult to create a console font from a monospaced TrueType font).

I like this answer:

setfont /usr/share/consolefonts/UbuntuMono-R-8x16.psf

this is an example; you can see a list of available fonts like this:

ls /usr/share/consolefonts

and should you for some reason not have them, you can install them like this:

sudo apt-get install fonts-ubuntu-font-family-console

note that you may need to put the setfont command in your .profile or .bashrc as it may need to be run upon every login