Syncing and editing pause: no new syncs start, and connectors and sync rules can't be changed. Your settings and sync history are kept. Renew the license from Manage license to resume.
A trial runs as the Evaluation edition: every Advanced feature, with a slower scheduled pull and a limited number of connectors and sync rules. When you buy Standard or Advanced, the trial limits are lifted and the limits of your edition apply. See License Editions for the exact limits.
See also: Installation Guide (Licenses expiration behavior)