A call for speakers is an open invitation for people to propose sessions, collecting topics, bios and session details for a program team to review.
A proposal form collects a title, an abstract, a format, a track, a speaker bio and usually a headshot. Ask for less than you think you need. Every additional required field cuts submissions, and you can collect the headshot after you accept someone rather than before.
The quality of what you receive is set by how clearly you described what you want. State the audience, their seniority, the formats you will accept, what you will reject, and whether vendor pitches are welcome. Vague calls produce vendor pitches, then organizers complain about vendor pitches.
Two hundred proposals is a real workload, and doing it in a spreadsheet is how events end up accepting whoever submitted first. Score against stated criteria, use more than one reviewer per proposal, and decide in advance what a tie breaks on.
Session and speaker proposals come in through the platform and move through an approval workflow before they are added to the event. Session reviewers can be added separately from admins, so a program committee can read and score proposals without being given the keys to the whole event. See speaker management.