Edit invoice when its send

Hallo .I am create invoice. when I save and send invoice how can I edit it??

Once you ‘save’ , it has status of ‘draft’ , you can still amend.
If you ‘submitted’ you can cancel and amend , after you amend a doc it will have a -1 at the end of the name series…
If you ‘submited’ and applied other docs like payment you will need to cancel these first.