Answer:
Step 1: Assign that member as beam type. (Midas, by default, will consider the line elements as beams if their local x-axis lies in the Global X-Y plane.)
Update the elements as beam member types; refer to the image below.
Step 2: Now, click the Beam Section Data for Design feature in the RC Design tab. Select the desired sections for assigning the reinforcements. Refer to the snap below for a better understanding.
How to assign reinforcements in RC tapered sections?
Reinforcement cannot be directly assigned to the tapered sections as in other standard sections.
As a workaround, kindly create an average section (middle section) and assign the reinforcements following the above steps.