Hot fill and hold
Updated
Hot filling sterilizes the container and closure with the product's own heat. It is simple, it needs no equipment beyond what you already have, and the details are where it fails.
What it does
Filling hot and holding the closed container inverted lets the hot product contact every interior surface, including the headspace and the underside of the cap. Those are the surfaces a cooling product never touches otherwise, and they are where spoilage organisms survive an otherwise good batch.
It also pulls a vacuum as the contents cool, which is the pop you hear and the dimple you can feel in a plastic bottle.
The sequence
Fill at the temperature your scheduled process specifies, commonly in the range above 180 degrees Fahrenheit for acidified products. Cap immediately. Invert for the specified hold time. Return upright and cool reasonably promptly.
Each of those numbers comes from your process, not from a general article. Temperature and hold time together are the control, and shortening either is a change to the process rather than a shortcut.
Where it goes wrong
Filling a tray of bottles and capping them afterwards. By the time the last cap goes on, the first bottle has cooled and the closure surface was never treated. Fill and cap one at a time.
Cooling too slowly in a stacked case, which holds the product hot long enough to dull the color and cook the flavor flat. Hot fill costs you some brightness; a slow cool costs you a lot more.
And the container. PET softens well below the temperature a hot fill needs, so a bottle not rated for it will deform, and the deformation is sometimes subtle enough to pass inspection and fail on the shelf.
When you can skip it
If your process does not call for it, do not add it. Some acidified products are safe cold filled, and a process authority will say which yours is. Hot filling a product that does not need it costs color and flavor for nothing.