Search engines are your friend! Here's the first item I found on searching "Backpacking White Mountains New Hampshire," in the reputable SectionHiker blog I check regularly even though I live at the opposite end of the country:

backpacking-in-the-white-mountains-a-quick-and-dirty-guide It has links to more detailed info sources. For the specific info you want, page down to "Permits and Regulations" and "Camping and Shelters," although the entire article is well worth reading.

Most trail guides will have camping suggestions for individual trails. The article above recommends guidebooks and maps.

Edited by OregonMouse (06/28/19 07:51 PM)
Edit Reason: additional info
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey