Does my search history show up on the wifi bill??

no, your search history does not appear on the bill. the bill just shows the plan price, any overages, taxes, and data usage totals. nothing about specific sites or searches.

HOWEVER. a couple things that ARE true:

• the router in your house has logs of which devices visited which domains (not full URLs usually). a tech parent could log into the router and see "jakesphone visited pornhub.com at 2am" or whatever
• if you use a browser where you're signed into a google account that's also on her phone, she can see your search history through google account settings
• apps like circle, gryphon, openDNS at the router level CAN log everything

so she's bluffing about the bill but could theoretically see stuff other ways

OP: omg okay that's a huge relief. she's def bluffing, i don't share a google account with her and i don't think we have any fancy router stuff