Dear Pratima, Start with fun activities like writing in different mediums (i.e., sand, foam, paint, wall, white board etc) and with different mediums (i.e., crayons, paint, colour pencils, chalk). Also, keep the writing relevant to your son (e.g., his name, your names, list of things to buy etc). Also, do other fine motor activities (e.g., playing with play dough clay, beading, lacing etc) to help develop those skills. Hope this helps!

my son is of the same age and doesn't want to write, but he enjoys joining dotted lines so i have made few patterns of the same and ask him to do atleast 1 page a day... with crayons or pencil

Let the grip develop don't rush give him activities tht help good pincer movements like putting pegs on cloths. Or dipper activer from one bowl to another or using a plucker and putting pasta from one plate to another .. any school eventually push to write and all learn don't wrry. Give him time.