While more patterns, prints, and styles are more socially acceptable nowadays, it’s still pretty typical for the immediate family to opt for black or dark-colored funeral outfits. Men often opt for a suit, but if not, some nice chinos or slacks, a blazer, button-down, and their nicest overcoat (if it’s chilly) will work just fine. Everything should be neatly pressed and cared for, not crinkled, wrinkled, or stained.
When searching for an appropriate funeral outfit women can wear, there’s a little more room for personality. You could opt for a simple dress (either plain or patterned), a matching sweater/skirt set, or even a pantsuit, if you have the right one. Choose tops with sleeves (length can vary) and pants or skirts should be of a professional length.
As far as footwear, choose something you can wear for an extended amount of time, especially during the outdoor portion. You don’t want to be yanking your stilettos out of dirt and mud just to get back to the pavement. You also probably want to avoid breaking in a new pair of shoes as a part of your funeral outfit. Go for something subtle. Also, some religions and cultures find it appropriate to wear a hat or veil of sorts to a funeral, but just be sensitive to the deceased and the other guests.