All-purpose flour
All-purpose flour is a medium-strength wheat flour used for everyday baking and cooking. It has enough gluten-forming protein for many breads and doughs, but stays tender enough for cookies, cakes, pancakes, sauces, and dredging.
Identity
Everyday wheat flour
Use it when a recipe needs a balanced flour, not a very soft or very strong one.
All-purpose flour sits between cake flour and bread flour. It can thicken sauces, coat foods before frying, and make tender baked goods. For very chewy bread or very delicate cakes, a more specific flour may give a better texture.
What's the Difference Between Bread Flour and All-Purpose Flour?
Reference image
All-purpose flour reference image.

Source: Wikimedia Commons
Used In Recipes
Substitutions
Bread -> All-purpose flour
500 grams bread or all-purpose flour (17.5 ounces; about 3 1/4 cups), see note
The source lists this as an alternative in the same ingredient row.
Source: Homemade Focaccia
All-purpose flour -> King Arthur Gluten-Free Measure For Measure Flour
1 1/2 cups (180g) King Arthur Unbleached All-Purpose Flour or King Arthur Gluten-Free Measure for Measure Flour
The source lists this as an alternative in the same ingredient row.
Source: Apple Cider Snickerdoodles
All-purpose flour -> King Arthur Gluten-Free Measure For Measure Flour
1 1/2 cups (180g) King Arthur Unbleached All-Purpose Flour or King Arthur Gluten-Free Measure for Measure Flour
The source lists this as an alternative in the same ingredient row.
Source: Quick and Easy Vanilla Cake