you can see the grn list from here and from the action button of each grn you have some special options.
from the view option you can see the further detail of relevant purchase(GRN) and edit you can edit the grn.
from the view payment you can see the payments of the grn and from add payment you can add payments fully or partially to the payment which have dues.
this is how you can add a payment to the grn.
you can take an invoice print from these options and also, you can delete the purchase from the system too.