When attaching a jig to a line there are many different knots one could use. Each possible knot has it’s own pros and cons – some might be stronger or easier to tie, for example.
There is one knot I consistently use with jigs because I feel it gives the jig that action which gets the fish to bite.
The knot is the non-slip mono loop knot. In reality any loop knot should work fine, but the non-slip loop knot is pretty easy to tie.
Having the loop allows the jig to change it’s pitch when jigged up and down, but return to level when still.
The loop doesn’t need to be big. Just large enough to give the jig plenty of movement.
When done it should look something like this (this example was tied with high pound test line for visibility in the photo).