If you are unable to find the Generate e Invoice option under GST Miscellaneous utilities,So you can check these things:
Step 1:First,You can check e invoice option is enable or not in GST/VAT.
Step 2:Go to Administration menu,click configuration,then click features and option,click GST/VAT,here you can enable and configure e invoice.
Step 3:Then you can Go Transaction menu,there is last option is GST Miscellaneous utilities, now you can see here is the option of e invoice management option,click on it,here is option to generate and print e invoice in bulk and E invoice Audit Report to check is there any invoice to generate or not.