How to Hem your Pajama Pantry Pjs
It's very simple, and shouldn't take you more than about 10 minutes if you have a sewing machine. It will take a bit longer if you sew by hand.
I don't recommend 'magic' iron-on hemming tapes - they are fiddly to use, and usually come off after a few washes.
If you don't want to sew, you can always roll up the bottoms, give them a quick iron and you'll look great (but be aware of fraying).