hi, dear ποΈ! can i assist you rq?
so, going from my own experience, it took me some time to understand how and where to make the dividers (you can search them like this here, too), and i can surely recommend photopea.com
so, when you enter the page, it will look like this
you go and press on 'new project'. next thing you'll see are these configurations:
so, on width is always 2000 but the height can be from 1 to 20 (i usually use 7 or 11, depending on my layout)
once it opens, you'll see this pre-made divider:
see this little colored square besides the white one? yes. you press on the colourful one, and it will open the colour picker (to put in the hex code you want):
i usually use the # because its easier to use, and you just need 6 digits + letters. once you do, press OK and go back to where you were. you'll see that there are gonna be no changes at first. so, you go here:
and press on edit. after you do, you'll see the button fill and without changing anything, press OK again.
ta-da! you have your colour. but you'll ask me "how do i download it then, soph?" and the answer is quite simple; you go on the bar below:
and press on the arrow that points downwards. i usually download it in the PNG format. then, i copy the image from my downloads folder on my laptop/phone and copy-paste it on my pinned <3
hopefully, it helps anyone!