Masking can mean covering an area to protect it during work, or concealing an odor or appearance. The intended meaning should be stated explicitly.
What this means at your property
Masking trim before painting protects a surface from coating. Adding fragrance after a smoke event changes the perceived odor but does not demonstrate removal of residue. These are very different tasks despite using the same word.
What should an odor-treatment proposal describe?
Ask which source or affected material will be addressed and how the outcome will be checked. If protective masking is proposed, identify the surfaces, duration and responsibility for removing the protection without damaging finishes.