come forward vs step up

come forward and step up both are verbs.

Word	Noun	Adjective	Verb	Adverb
come forward	No	No	Yes	No
step up	No	No	Yes	No

As verbs, come forward and step up are synonyms defined as:

Other synonyms of come forward include come out, come to the fore, step forward, step to the fore.

come forward (verb)	step up (verb)
make oneself visible; take action	increase in extent or intensity
	speed up
	make oneself visible; take action