is it possible to change how the pipboy looks like in FNV?

I think he's asking if it's possible to change the FO4 PipBoy like you could in NW (I.e Readius 2500 etc.)

Yes there are ways to change how it looks , there is the pimpboy 3 billion in game , and multiple modding ways to change it .

Those mods already exist so you places your topic right.

like change the pipboy into an phone strap. if it is possible why is no one doing. im trying to learn how to mod but idk what to use for textures and how to sculpt armor/weapons i use nifskope and blender

farcry armor mod and weapon mod

There is a whole pile of pip boy mods on nexus, just download few and check how they made. If its for personal use, just retexture or even remesh them how you like. There are planty pip boy mods