A 毛笔字 is literally "a character written with a brush" or "brush-written characters". But the English word you're looking for is most likely "calligraphy". Calligraphy is elegantly written text, usually using a brush or special pens. 网红(anything) is "internet famous" or "famous on the web/net. So 网红奶茶(店) is literally a milk tea place that's internet famous because people like it, take pictures of it and upload them to the internet. There's really no exact equivalent to "网红奶茶", so here's my own translation: milk tea that's famous on the web.