paper
紙 centers on the material made from plant fibers: paper. It is the everyday word for sheets used for writing, wrapping, and crafts.
紙 combines 糸 (thread, silk) with 氏, which likely contributes the sound. The character originally referred to a type of silk fabric, later extended to paper made from plant fibers.
The left side 糸 suggests fibers or thread, and the right side 氏 looks like a sheet being pulled from a stack. Picture threads pressed into a flat sheet: that's paper.
For シ, imagine a sheet of paper with the word 'she' written on it: she -> シ, and the paper holds the message.
paper
letter; note
cover (of a book, magazine, etc.); binding
wallpaper
blank form
paper money; note; bill
white paper; flyleaf
space on a page (e.g. in a newspaper)
origami; art of paper folding
square fancy cardboard, used for autographs, poetry, etc.
paper bag
newsprint; newspaper used for wrapping, packing, etc.
washi; Japanese paper
kamishibai; storytelling with pictures; form of Japanese street theater and storytelling (popular from the 1930s to the 1950s)
(revenue) stamp
paper patch attached to something; paper backing; sticker; label
main section (of a newspaper); central column
cardboard; thick paper
papermaking; paper manufacture
drawing paper
wastepaper; scrap of paper; paper scraps
used paper; paper for recycling
on paper; in the newspapers; in a letter
aluminum foil; aluminium foil; tinfoil; silver paper