Step 1: Create custom field for your issues

Now you need create a custom field for issues, follow steps:

1) Go to Settings → issues

2) Go to Custom field → click on create custom field

3) Find MLCS (Advanced → Multi Level Cascading)

4) Set a name

5) Select all screens and context where you need custom field

6) MLCS now are available on any issue

Step 2: Add Options

1) Click on the three dots, then select "Contexts and Default Value."

2) Click "Edit Custom Field Configuration."

3)You can now add the field configuration and click Save