Search

Press F3 or / and start typing in the process name to search: highlights closest matching result amongst all entries.

Filter

If you only want results matching your query to be shown, you could filter instead: press F4 or \ to filter

From the htop manual:

F3, /: Incrementally search the command lines of all the displayed processes. The currently selected (highlighted) command will update as you type. While in search mode, pressing F3 will cycle through matching occurrences.

F4, \: Incremental process filtering: type in part of a process command line and only processes whose names match will be shown. To cancel filtering, enter the Filter option again and press Esc.