Underscore
Underscore (verb)/ˌʌn.dəˈskɔːʳ/ US /-dɚˈskɔːr/
1. to draw a line under a word, phrase, etc. to emphasize its importance – underline:
Underscoring while reading is a consciousness-raising technique.
2. to put emphasis on something – emphasize:
She underscored the plot of the story by dint of dramatization and visual aids.