Queso blanco means white cheese, and the name covers more than one fresh cheese. In US markets it usually means a pressed fresh cow's-milk cheese that holds its shape in a pan.
That is the useful split with queso fresco. Fresco crumbles onto food. Blanco, in that shopping sense, can be fried. Neither is a long-aged cheese, and neither stretches like Oaxaca.
History
The words are a description, not a birthplace. Across Spain and Latin America, queso blanco can mean any white cheese the speaker has in mind, fresh or not. In the United States, cheese companies and Mexican groceries narrowed the name toward a fresh cow's-milk cheese that you can fry. That narrowing is a retail habit. It is useful, and it is not a law of every Spanish-speaking kitchen.
The frying cheese is often set with acid, in the same broad family as paneer, which is why the slab browns and keeps its edges. Other white cheeses are set with rennet and crumble. Because both can look like a white disk in a shop, the name on the label has to do more work than it can. The history that matters for a cook in a US shop is this modern distinction, not a single town of origin.
How it is made
A frying queso blanco is made by curdling hot milk, pressing the curd into a firm block, and selling it fresh. Acid-set versions behave most like paneer: heat firms them and browns them, and they do not melt into strings. The block is white, moist, and usually lightly salted. It has no rind and no age.
A cheese under the same name in another country may be a fresh white cheese of a completely different firmness, or simply any cheese that is not yellow. If you are shopping in the United States for a recipe that says to fry queso blanco, buy the one that says it fries or grills, or buy the firmer block rather than the one labeled fresco. If you are reading a Latin American recipe, look at the method. A crumble added at the end is fresco behavior even if the writer said blanco.
Taste
The US frying cheese tastes mild, milky, and lightly salty. Browning adds the flavor the raw cheese lacks. It should taste clean and fresh. A sour block is old. Herbs or chiles, if they are present, were mixed in and should be listed.
Do not expect the sheepy tang of feta or the savor of an aged cheese. Do not expect a strong funk. If the fried slab tastes bitter, the pan was too hot or the cheese was stale. If it falls into wet crumbs, you fried queso fresco by mistake, or the block was not the firm style. The taste of a correct piece is quiet milk with a toasted surface.
In the kitchen
Fry or grill slabs until the faces are golden, and eat them with a salsa, in a torta, or beside eggs. Cube the firm cheese into a simmered dish when you want it to stay in pieces, in the way paneer stays in pieces. Crumble is the wrong default. If your block crumbles, treat it as fresco and change the recipe.
Do not buy it for a quesadilla that must stretch. Add Oaxaca or Chihuahua for stretch, and keep blanco for the part that should stay in slices. Paneer is the best technical substitute in a fried or simmered cube. Halloumi is the substitute when you want more salt and a squeak and can adjust the seasoning. Queso fresco is the substitute only for a garnish of crumbs.
Around the world
In a US Mexican market, queso blanco as a frying cheese is a practical staple. In Mexico and elsewhere, a person who says queso blanco may be pointing at a fresh cheese that is not this slab at all. The words traveled, and the meaning did not stay in one box.
This page uses the US market distinction because that is how the two catalog entries, fresco and blanco, stay useful. When you cook from a recipe, follow the verb. Fry means the firm white cheese. Sprinkle means the crumble. If a recipe uses the words without a verb, look at the country of the writer before you choose a disk.