What is a presidential exploratory committee?
The announcement made clear that Warren is in the race for the Democratic nomination, but by forming an exploratory committee, she is technically still one step short of officially becoming a presidential candidate.
An exploratory committee is a vehicle by which candidates for federal office can "test the waters" of a bid before officially entering a race.
...
Brendan Fischer at the Campaign Legal Center, a nonprofit group focused on campaign laws, explained that the FEC "allows an individual at the testing the waters stage to voluntarily form an 'exploratory committee,' and to voluntarily file reports disclosing contributions and expenditures, but there is no legal obligation to do so until they become a candidate."
"A candidate or potential candidate is under no legal obligation to form an 'exploratory committee'— but a presidential hopeful can create multiple opportunities for news coverage by first announcing the creation of an exploratory committee, and then later announcing their campaign," Fischer said.