Using System fonts in p5.js is quite simple. You can also load your own fonts and use them to type on the canvas
let myFont;
function preload() {
myFont = loadFont('helvetica.otf'); //load your own font
}
function setup() {
fill(0,0,255);
textFont(myFont);
textSize(36);
text('p5*js', 10, 50);
}