"Set in motion" is a common phrase used to describe the act of beginning or initiating something. However, there are many synonyms that can be used to convey this same meaning.
Some alternative phrases that could be used include "get the ball rolling," "commence," "start up," "initiate," "trigger," "activate," "launch," and "kickstart." Each of these words or phrases highlights a slightly different aspect of beginning a task or project, but they all imply that action is being taken to move things forward.
By incorporating these synonyms into your writing or speech, you can add variety and emphasis to your language and enhance your ability to convey meaning.