3GPP 21.900 v20.0.0 — the document's own text

7.5 Electronic tools used/preferred

Taught in 9. Why the documents read the way they do (How standards actually get made, in depth), 15. Reading either body's paper trail from a cold start (How standards actually get made, in depth).

For the various types of documents and parts of documents of 3GPP, a minimum variety of word processors etc. should be used. Those identified in 3GPP TR 21.801 [1] are permitted.