Hello, for soft and smooth hair,
-henna is very good (it changes the door a bit though) -conditioning is very important after shampoo.
-deep condition your hair every 15 days.
-oil them regularly.
-give steam to your hair while deep conditioning, using hot towel.
-eat protein rich foods.
-stay away from curlers or flat irons.
-if you use hair plop method to dry your hair, they will dry softer.