I have made a customised document on documents submit event I want to make stock entry for manufacturing and delivery note in sequence, I tried to do that it shows that there is no stock available in the warehouse.
There is a transaction workflow over there. Database API
You need to commit your transaction.
https://frappeframework.com/docs/v13/user/en/api/database#frappedbcommit
PS: Did you also submit your stock entry. Can you examine Stock Entry? Also Delivery Note time should be 1 second later.