Total upwork connects is 60. Each job contain 2 connects. After one month Your connects renew. For applying on job you should make attractive cover letter. Apply only on those job you think you can do.
A connect is what you use to bid on jobs and send proposals. The free basic plan comes with 60 connects a month and the plus plan comes with 70 connects plus some other features which you can read about here.
Please read this help article for more information how to create 100% complete profile on Upwork