How can I make this look better?

[Shinyandnew1]

This is the gap between the door frame and the walls. I presume it's filler or something but it's cracked and looks crap.

What can I fill it with to make it look better??

Erm, filler?

If you dig it out using a blade (to clean + widen the crack), fill with filler, sand, prime then paint it’ll look good as new!

I saw CT1 recommended on another thread. I haven't tried it yet but intend to as painter's caulk ends up looking like that more often than not.

https://www.mumsnet.com/talk/home_decoration_pictures/5371626-filling-gaps-above-skirting-board

Agree, you need to scrape out the loose stuff, make it wider and smooth it down flat before filling it.

You could finish it off with a piece of trim, flat, rounded or decorative. Filler won’t look great and will probably crack again.

Scrape out the loose bits, sand it down, filler, sand it, prime it, paint it.

Scrape out, CT1, paint