You can create as many ticket forms as you need but you are only able to publish the amount allowed by your helpdesk plan.
Please check the plan table to find out how many are allowed by each plan. Manage> Account Information> View or Change Plan.
In version 2 of Mojo Helpdesk you can access the plans by clicking the drop arrow next to the settings icon (wrench) and choosing Helpdesk Settings. Then choose 'Plan and Billing'.