There is an option rlheme.loadfonts which -- if set to TRUE -- will call extrafont::loadfonts() to register non-core fonts with R PDF & PostScript devices. If you are running under Windows, the package calls the same function to register non-core fonts with the Windows graphics device.

import_lato()

Note

This will take care of ensuring PDF/PostScript usage. The location of the font directory is displayed after the base import is complete. It is highly recommended that you install them on your system the same way you would any other font you wish to use in other programs.