1. Begin by navigating to Settings.

2. Next, find and select 'Custom Fields'.

3. Proceed to click on 'Add Field'.

4. Select 'Multi Line' from options.

5. Then, progress further by clicking 'Next'.

6. Have a quick view of the 'multi-line' field.

7. Now, it's time to name your field.

8. Choose a group for your field here.

9. Afterwards, define the object of your field.

10. Provide a placeholder for your field. A placeholder in a text field is text that appears within the field as a hint or example of the type of information that should be entered.

11. If needed, add a prefill value for the field.

12. For more specifications, add 'Additional preferences'.

13. Customize the unique key of your field here, if desired.

14. Fortify your field with a useful description.

15. Finally, Click here to 'Save'
