How do I include the indirect costs incurred, to my projects?

Indirect costs are usually referred to as overhead expenses and general and administrative expenses. Few examples are rent, legal fees, officers’ salary, etc.,

To associate these costs to a project in Zoho ERP:

Go to Time Tracking on the left sidebar.
Navigate to the Projects module at the top.
Select the project for which you need to record an expense.
On the top of the page, click New Transaction and select Create Expense.
Enter the expense details for the project. The Customer and Projects field, billable option will be automatically populated.

Insight: Select the type of indirect cost you want to associate with this project from the expense account drop down. You can also add a new account by clicking + New Account from the dropdown.

Click Save or Alt+s.

By marking the billable checkbox, you will be able to invoice the customer for this expense.