Almost any bread flour, from white to whole wheat will do.
Here's where I got my inspiration, but exact measurements/weights are not given: https://madhurasrecipe.com/breads/how-to-make-chapati
For a variation, see: https://madhurasrecipe.com/breads/plain-paratha-marathi-recipe
(Chapati / paratha, to-may-to / to-mah-to.) There is a video in each one too.
Here are some formulas I've worked up:
Bob's Red Mill WW (red wheat): 2% salt(3), 68% H2O, 2% oil(1).
50% AP, 50% Bread flour: 2% salt, 55.8% H2O, 2% oil(1).
Stone ground whole grain durum: 2% salt, 66.7% H2O, 3% oil after 2 hours(2)(4).
Sher Fiber Wala durum: 2% salt, 74-75% H2O, 1-2% oil(1). Let rest at least one hour after adding oil for best results.
Golden Temple durum, white/red bag: 2% salt, 62-63% H2O, 2% oil(1).
Swad durum semolina (the gritty stuff): 2% salt, 57% H2O, 2% oil after 30 minutes(4).
Regular durum semolina is low bran (it has some) so it doesn't take much water. Also, because you have to let chapati dough rest a while, the grittiness eventually goes away.
Note (1): mix/knead to a homogenous dough before adding oil. I like the flour to be hydrated first, then get to the oil.
Note (2): this particular flour takes a long time to hydrate, so give it at least two hours before adding oil.
Note (3): In all these, salt can be reduced or eliminated if the chapati is to be served with a salty/savory dish.
Note (4): In the cases where you have to let the dough rest at least 30 minutes before adding oil, let it rest at least 15 minutes after adding oil.
Important: You must let the dough rest at least 30 minutes after mixing before rolling out. If using all white flour, you can rest it for less time, but at least 15 minutes.
The uncooked dough can keep a day or two in the fridge. I use a plastic bag with the air squeezed out.
Tortillas/chapatis are as much about rolling technique and cooking technique as they are about the ratio of ingredients.
For instance, rolling out, wiping on a little oil and flour, foldng, and rolling again, gives a layered chapati. But this is optional.
Use a sprinkle, maybe 1/8 tsp of white flour per side, to keep the chapati from sticking when you roll it out. This should also keep it from sticking on the griddle. White (refined) flour is best for this step as it absorbs into the surface quickly.
Coarsely ground flour at this point will not have time to soften. So use store-bought white flour for dusting at this point, if using home-milled flour for the chapati.
You want the surface of the chapati to be dry enough to not stick, but the inside of the chapati needs moisture that will eventually soften the chapati as it cools after cooking.
I like about 30 grams of _flour_ per chapati, so for the BRM-WW above that would be 30*1.72 = 51.6 grams of dough.
I roll these out to about 7" diameter.
These are cooked on a dry flat griddle or pan/skillet on the stove top. The video in the above Madhura's recipe shows how.
There are two ways to go when cooking: lower heat (electric burner setting 2 to 3 out of 10) for 2-3 min per side, or medium (electric burner setting 4 to 5 out of 10) for 45-60 seconds per side.
I give 30 seconds to the first side, flip, then give it 60 seconds checking to see where brown spots are, pressing down with spatula or paper towel where needed, flip again, and give it 30 seconds, checking and pressing where needed.
You can let it puff up, using a spatula to help it along, or poke the bubbles to keep it flat. I like keeping it flat. See Madhura's chapati video (1st link above) for how to roll it and cook it to get it completely puffed up.
You want to cook each side until you get brown spots, but don't make the surface crispy, or it won't soften after cooking.
After cooking, it needs to be enclosed in something so that the moisture equalizes, and the surface softens. I give mine 15 minutes. More or less might work too.
I use a "tortilla keeper" like this one: https://www.amazon.com/Norpro-1065-Tortilla-Keeper/dp/B000PB30BU?tag=froglallabout-20
This is the tricky part, but you have to cook it just right in the first place so that the inside is cooked to "done" and at the same time enough moisture is left to soften the whole thing. So you also have to get the dough to the sweet spot in terms of hydration too.
If you are going to re-cook the chapatis as part of a recipe, such as a quesadilla or as a base for a pizza, then you could undercook one side (no spots), the side that will be exposed to the hot surface in your quesadilla/pizza.
Tip: Chapatis are like pancakes, in that I usually mess up the first one in a batch. ;-)