I have a wave that all pick tasks are completed but it still hasn't generated the item fulfillment. What can be causing this? How can I manually trigger an item fulfillment?

It takes sometime time to process them. Click on match button on the pick task to trigger process again.

If I click match on one pick task it will create an item fulfillment for all lines?

For that sales order. Normally it breaks when IF is created in the UI for same lines.

That's what I need thanks.