EF Core tracks objects' states through the ChangeTracker type. Every object that is retrieved from the database is automatically tracked by the ChangeTracker, and every change that is made on it changes the object's EntityState to Modified. If a retrieved object is removed from DbSet (or if an object that contains it is removed), EF Core will change the EntityState value to Deleted. 
When EF Core SaveChanges is executed, it scans the tracked objects, and if they are modified or deleted, EF Core generates an UPDATE statement with the relevant modifications that are needed, and a DELETE statement for the deleted objects. 
Here is a code snippet that shows how to update a product and then delete it:

var product = await _context.Products.FindAsync(id);
product.Title = "I've changed";
await _context.SaveChangesAsync(); // The entity is updated in the DB
_context.Products.Remove(product);
await _context.SaveChangesAsync(); // The entity is deleted from the DB

After data is stored in your database, it's natural that the next thing will be to create queries to retrieve it. Luckily, we don't need to learn SQL to query the data; instead, we can use the EF Core Querying API.