There are several ways to make repeating tasks.
Creating a new task and setting it to repeat
If you are the New Task panel to create a new task, you can click on the "Set color, repeat and more" button to set the repeat frequency.
Making an existing task repeat
Simply locate the task in question, hover your cursor over the due date column, and click on the "Repeat" icon to set the repeat frequency. Please note that this icon will only be available when the task isn't checked off, and that it has a valid due date.