A call for papers (CFP) is a special type of invitation for scholars, academics, and professionals to submit papers or abstracts for presentation at a conference. Conference organizers use CFPs to solicit content for their events. A CFP may be issued for presentations, workshops, posters/demonstrations, panels, roundtables, performative lectures, installations, or other events. 
Conferences

When issuing a CFP, conference organizers generally specify the theme or focus of the event as well as the format (presentation types) they are seeking. This helps prospective presenters determine whether their work would be a good fit for the conference. For example, if an organizer is looking for 20-minute presentations on innovative teaching methods in second language acquisition classrooms, then a paper on using drama to teach vocabulary would likely be appropriate. 

If an organizer wants proposals for 90-minute panel discussions featuring four experts on current environmental policy issues in Southeast Asia, then a paper discussing one particular environmental issue in that region might not be the best fit.

In some cases, submission deadlines will be very specific (e.g., “Proposals must be received by January 15th”). In other cases however, organizers may simply state that proposals will be accepted “until the program is full” – meaning that there is no firm deadline and submissions will be reviewed on a rolling basis until all slots are filled.