Company that will fill plastic hot sauce bottles. How do I do a search for US companies that fill food/sauces into bottles. This would mean that they would do the final seal? I'm confused if the bottles would then come to them labeled, but they filler would steal have to place a final seal onto the plastic bottle.

Slightly confused here.
What is YOUR position in all of this ?
Are you producing the Hot Sauce and looking for a bottler?

The company that fills the bottles, will ( large company) have machines that place the bottles on a conveyor belt, they go down the line and are filled, then they have the top placed on them and are sealed. Then the label is placed on the bottle and they are packed to a case.
Even the case is sealed automatically.

So you would be looking at 10s of thousands of bottles.

How many thousands would you be ordering at a time?