Hello! Ive recently started delving into sigil creation and have a potentially silly question. All the intention statements ive come across all have “I” in them. I want to create a sigil that will benefit my whole family, can i use “We” instead?
Yes, your sigil is your creation and you can make it to be anything you want. 
Yup, you can use “we” instead of “I”. Then, as long as the sigil is placed in a communal area or burned in a communal space it will affect everyone instead of just you.
My intention is to embroyder it on our bed sheets. Nobody has been sleeping well
That absolutely works! To make it even more general, you can create the sigil with a phrase about anyone who uses the sheet will get a good night’s sleep 
then if you have guests or someone else uses the blanket, they’ll sleep well, too!