For creating job work entries, follow below steps:
You can enable invoice types on Settings > Template Settings > Header > Enable Invoice Type
There will two invoice headings here. One should be 'Tax Invoice'. Second should be 'Job Work'
Now, while creating the invoice, you will see an option of changing invoice type, switch to Job Work, change invoice number as per your own requirement.
After saving this job work, your inventory will get reduced.
After job work completed and inventory is back, create a Credit Note or Sales Return transaction to increase your inventory.