How to apply border on the right and bottom only

How to apply border on the right and bottom only

Step 1 > Draw the Shape and check the Property Panel (make Border 0 pt)

Step 2 > Right click on Layer and Select the Blending Option

Step 3 > Select the Inner Shadow 

Step 4 > Select Blend Mode Normal and Set color of Shadow

Step 5 > Move the angle to -45

Step 6 > Set the size of shadow (border) as per your requirement.

Result:-

How to apply border on the  bottom only

Same above steps you have to follow only change the Angle of the Shadow.

Result : -

How to apply border on the Top only

Same above steps you have to follow only change the Angle of the Shadow.

Result : -

Conclusion:-

Only need to change the Angle and see the Preview and you can give the border as per your need.