When is it safe to introduce a pillow and blanket? My son is 16 months old

Blankets can be used from birth as long as they are tucked in & there is no risk of baby’s head & face being covered.
Many parents choose not to use a blanket as baby becomes more active & is rolling, as they tend to not stay under blanket & may “kick it loose”
Red Nose recommends to withhold the use of pillows until baby is in a bed & at least 2 years of age.
https://rednose.org.au/article/at-what-age-can-i-introduce-cot-bumpers-and-pillows
https://rednose.org.au/article/can-baby-use-a-pillow-to-prevent-flat-head