Add special text and sign marks to measures

Question

I wonder what is the best way to add the yellow signs and text (attached) in LilyPond code?

Answer 1

For compressed multi-measure rests, use \compressMMRests { }.
However, the default is set to use multiple rest symbols for rests that are 10 bars or less. To get a small number of rest to compress like in your image, you will need an override:

\override MultiMeasureRest.expand-limit = #1
\compressMMRests {R1*4}

see: https://lilypond.org/doc/v2.23/Documentation/notation/writing-parts#compressing-empty-measures

---

To write rehearsal marks, just use \mark\default, but to get letters in boxes you will need to set the mark format:

\set Score.markFormatter = #format-mark-box-letters 
\mark\default

see: http://lilypond.org/doc/v2.23/Documentation/notation/bars.en.html#rehearsal-marks

---

The segno and coda (symbols) are entered with \segno and \coda,
and to get "D.S. al coda", "To Coda", etc. enter them as simple markups:

    g'1^\markup{\bold "D.S. al Coda"}