Thanks to Riley and Tactical, full screen mode is available on Windows 10. There are 2 methods:
For win10, set the infantry client( not the launcher ) to game mode.
To activate Game Mode, open your game, then press Windows key + G to bring up the Windows 10 Game Bar. Click the Settings cog on the right side of the bar to bring up a bunch of options. Check the box next to Use Game Mode for this game near the top. Once you’ve done so, simply close the dialog box and Game Bar to get going. There’s no need to restart your game for Game Mode to take effect, though you do need to manually enable the feature for each and every game you want to use it with.
Drawback is you can't see chats.

Second option:
For all you steam owners, search and download borderless gaming then open infantry. Add infantry to the list in borderless gaming and have fun. This is a dollar on steam but there is a free one out there.

Free version of Borderless Gaming available on github, https://github.com/Codeusa/Borderless-Gaming/releases

This is the only way I could get Windows 10 to fullscreen Infantry without making it look like shit or lagging really bad.

Fuck you Cortana lol.

Much obliged, friends.

I already thought the game mode thing was common knowledge but no one used it because of the chat shit.

I think I did this and did it correctly, but it didn't work.

Do I have to download that program?

Should sticky this :)

Any idea how to make it so you can change resolutions also?

Having borderless is nice and all but I'd prefer to not be stuck in Windowed Mode.

You can't as far as I know. I haven't heard of anyone changing resolutions with win10.

That sucks