To Create an Recurring Invoice for a contract, follow these steps:

Step 1: Head to the "Billing" section in the side navigation bar and choose "Recurring Invoice" from the list.

Step 2: Once you have accessed the recurring invoice section, you will see an option labeled "Recurring Invoice +". Click on this button to create new recurring invoice.

Step 3: A new window will open where you need to fill in the fields including the customer, contract, template, starting date, Bill cycle and end date appropriately.

Step 4: To add a new item into the categories of 'Ad-Hoc' and 'Product & Expense' there exist corresponding options labeled 'Item+' and 'Product & Expense+'.

Finally save it by clicking the save button located above.

(NOTE: The Recurring invoice can only be created using Fixed contracts. And Products and Expenses added will be billed accordiong to the Bill cycle you have set. Recurring invoice will be listed in the draft area and user has to generate invoice from there manually.)