What age is it ok to give a pillow to a toddler ?

While your toddler is out of the age range for SIDS, Red Nose recommends not introducing a pillow till a child is in a bed.

Older babies in a cot can be at an increased risk of a sleeping accident by using pillows and bumpers as a step to climb up and fall out of the cot.
It is safer to wait until the child starts to sleep in a bed before introducing a pillow or other soft bedding.
https://rednose.org.au/article/at-what-age-can-i-introduce-cot-bumpers-and-pillows