Materials markups are much more straight forward than labour. Simply specify on each job a percentage markup for materials purchases that are posted to that job. Again, you’re going to navigate to the job entry screen. Select item [e] Job Costing on the navigation panel, and under that heading, select item [a] for Job Entry:

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On the Job screen, enter your material markup:

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When you bill a client for a job, the billing utility will pick up any materials posted to that job, and apply the materials markup to the total amount of the invoice. This amount will be billed to your client.