Can I use “All-Purpose flour” instead of “cake flour”? [duplicate]

This can depend on the specific recipe and the goal, but in general know that cake flour has a lower resulting gluten content than all-purpose flour, thereby resulting in the cake having a "lighter" texture. Experimentation with the specific recipe can tell you whether it matters, but in general I would caution substituting if any of the following conditions are called out by the recipe;

• a very specific kneading/mixing time, i.e. with breads
• a specific attention is called to the temperature, i.e. with pie crusts
• the cake should have a very fluffy, spongy, or otherwise specific texture (as opposed to a more loose end result as with cake brownies or other hybrids where some flex either way could yield a nice result)

In some recipes, and especially mediated by the type of fat you use*, it may not matter if you use cake flour. However, if you want to make a spongier or fluffier loaf of cake, it will be detrimental to have all-purpose flour as the main building block. Some recipes can be specifically cut with cake flour to reduce gluten in the end result. The inverse obtains as well.

*If a recipe with a higher gluten flour calls for a room-temperature liquid fat (canola oil), and you substitute it with a lower gluten flour and a room-temperature solid fat (i.e. coconut oil, shortening) you can tweak to approximate a similar end result with pleasant nuances. I do this with otherwise oatmeal and whole-wheat cookies relying on a puree (i.e. pumpkin, sweet potato) for flavor, and cut in some APF with coconut oil instead of vegetable oil, thus resulting in a crisp cookie with a pleasant toothiness.