If Marloo has shared a promotion code with you, you can apply it when you upgrade your plan. The code is entered on the Stripe checkout page, not inside Marloo itself.
Steps
In Marloo, go to Settings > Billing.
Click Get Plus or Get Pro, depending on the plan you want.
The Stripe checkout page opens in your browser.
On the checkout page, click Add promotion code.
Enter (or paste) the code you were given and confirm it. The discount is applied to the total before you pay.
Note: if your firm belongs to a network or licensee with a pre-arranged Marloo discount, that discount is applied automatically at checkout and the promotion code field is not shown.
If your code is not accepted, contact us on the help chat and we will check it for you.